Tag: Fishkeeping

Aquarium Water for Plants: What I’ve Learned After 25 Years of Freshwater Fishkeeping
I’ve been doing water changes on my freshwater tanks for over 25 years, and for most of that time I’ve been routing that water straight to my garden instead of down the drain. As long as your tank is freshwater and hasn’t been medicated, that nutrient-rich water is liquid gold for plants. I’ve seen the difference firsthand. Here’s everything you need to know about using aquarium water on your plants and why it works so well.
Key Takeaways
- Aquarium water is rich in macro and micronutrients, like nitrogen and phosphorus, that are commonly found in popular fertilizer options.
- The parameters of your tank water may be influenced by tap water, food ingredients, and fish output.
- Chemically treated water should not be used on edible plants.
- Aquaponics is a large field in agriculture and encourages growing plants in a fish-based system.
Why It Works

Before we can see how fish tank water can be used to feed terrestrial plants, we need to understand what makes this water special. Like anything in the aquarium hobby, it all ties back to the nitrogen cycle.

I’ve always thought of my water change water as free fertilizer. Instead of dumping it, I walk it straight to my garden beds. my freshwater community tanks produce some of the richest free plant food you can find.

When you cycled your tank, you needed to introduce a source of ammonia into your aquarium. This could have been done organically or chemically. After a while, beneficial bacteria started to reproduce and process the ammonia into other compounds, like nitrite and nitrate. Once enough bacteria had populated the aquarium, ammonia and nitrite could be maintained at 0 ppm while nitrate was controlled through water changes.

Just because ammonia and nitrite aren’t readable in your current tank through test kits doesn’t mean that they’re not present though. In fact, fish are constantly creating ammonia through respiration and waste. Most test kits don’t read to this precision.

Plants and Nutrients

If you have a freshwater aquarium, you may have been recommended to add live plants to help cycle the aquarium and to keep an overall healthy system. There is a good reason for this! As we’ll see, aquatic plants are very similar to terrestrial plants in how they rely on nutrients; aquarium plants get most of their nutrients through the water column, though sometimes through the substrate, and most terrestrial plants rely on the soil to receive nutrients.

Plants can absorb all of these nitrogen compounds: ammonium, ammonia, nitrite, and nitrate. Most species uptake nitrate the most, but live plants can help maintain the other levels. This is why adding live plants to an aquarium can decrease the toxicity of the water and maintain levels in the future.

It’s important to note that freshwater aquariums also contain other important compounds, like magnesium and phosphate, that aren’t regularly tested for. Just because hobbyists don’t monitor these parameters doesn’t mean they’re not present in the aquarium. As we’ll see, they’re some of the most important compounds for growing terrestrial plants!

How can our fish tanks help our indoor plants and possibly even help grow the food that we eat?

Plant Fertilizer

The next time you go into an outdoor store or gardening center, take a look at the available fertilizers. You may see a variety of powder and liquid options, each of which will provide a percent breakdown of the nutrients offered.

You will likely see a ratio of three values on the front, which read N-P-K¹, or nitrogen-phosphorus-potassium. These are some of the most important nutrients for plant growth, and the ratio needed will depend on the species of plant being grown.

While you likely won’t get this precise ratio with fish tank water, nitrogen, phosphorus, and potassium are present in your aquarium. While nitrogen is predictable, phosphorus, potassium, and micronutrient levels will vary as they are influenced by tap water, food ingredients, and other inputs.

Now that we know how aquarium water acts as a fertilizer, how can we use what we have?

Watering and Water Changes

The best way to use your aquarium water as a plant fertilizer is by not wasting what you already have! More than likely, you perform water changes on your aquarium anywhere from once a week to several times a month. Chances are that you’ve been throwing that old water down the drain.

Before you get rid of that water, get a watering can! Use an aquarium siphon or cup to remove the water from the tank and into your container. As long as there isn’t a ton of fish waste or other organic debris, this water can be directly used to water plants. It really is as easy as that!

Python Cleaner

The Python is a mainstay in the fish hobby. Easily clean your aquarium by connecting this to your sink!

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If you’re siphoning your substrate during your water change, then you may want to take some time to let that gunk settle at the bottom of your container. While it is unlikely to hurt your plants, fish waste left sitting on top of the soil can attract other garden pests and lead to a nasty smell.

But wait! Don’t throw that fish poop out either. In fact, this organic matter can be directly added to a compost pile along with any excess water.

Storing Water

Unless you have a ton of plants, you’ll probably end up with leftover water from your fish tank. This water can be discarded as usual, or you may consider setting up a reserve for later use.

This reserve is like setting up another fish tank but in a closed tub or bucket. Here is one way of setting up an aquarium water reserve:

Use a bucket, tub, or other large container. This container should not let light in as this will facilitate algae growth that will end up stealing nutrients. In the worst-case scenario, this nutrient-packed algae can be used for composting!

This container should also be closed so that no contaminants, like aerosols, insects, or a thirsty pet, can make their way in. If you use a trash cute, the Brute brand is a great mainstay in the hobby. Make sure it is labeled as food grade.

Use filter media. Contrary to popular belief, beneficial bacteria do not live in the water column. Instead, they live on the surfaces in our fish tanks, mainly in porous filter media. While new amounts of ammonia or nitrite are unlikely to enter your container, beneficial bacteria will continue to make your used fish tank water a healthy environment. You can also squeeze out your sponges during water changes to release some of the bacteria and the nutrients.

Install a pump. Even though this water will be processed by beneficial bacteria, stagnant water will still invite unhealthy microbes. Stagnant water will likely grow algae and other slime while also depleting the water of oxygen. This could create anaerobic conditions, which would not be healthy for ornamental plants.

Check your water regularly. Fish tank water won’t store indefinitely, and we don’t recommend hanging onto it for more than a week, especially if there is sediment or other organics present. If you notice a funky smell or any other signs of contamination, dispose of the water.

Indoor Plants In Your Aquarium

Aquarium water can be used to water plants with a watering can, but it can also be used straight from the source. Many hobbyists have begun growing indoor plants, and even some fruits and vegetables, straight out of their aquariums. This removes the need to store water and gives plants direct access to some of the best plant fertilizers available. In return, the plant helps remove excess nutrients from the water column.

In order to grow terrestrial plants out of your aquarium, you will need an additional grow light. Also, some plants cannot have constantly submerged roots, so some special selection is needed.

Considerations When Using Aquarium Water For Plants

Aquariums make some of the best plant fertilizers available, but you might have a few questions about keeping healthy fish and healthy plants.

Should you add more nutrients directly into your aquarium?

It would make sense that adding more nitrogen compounds and other nutrients to your aquarium would make your fertilizer even better, but aquariums have a delicate balance of parameters. Too much ammonia or nitrite can lead to poisoning your fish; even high levels of nitrates can eventually impact your aquarium.

However, many hobbyists add nitrogen additives to their aquariums to help their aquatic plants grow. In moderation, this is a great way to facilitate growth and even get more desirable colors out of your live plants. In terms of dosing other macro and micronutrients, like magnesium and phosphate, it’s generally not necessary unless you are certain your aquarium is lacking in them.

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Being able to water plants with fish tank water is an added benefit of your aquarium, not its main purpose (though we’ll discuss more in the aquaponics section later).

Should you be worried about aquarium chemicals?

Yes, there are some potential hazards associated with using fish tank water that has been treated with chemical products. This is especially a concern if using the water on edible plants.

Most hobbyists dose their fish tanks with at least one chemical. Most often, this is a dechlorinator that removes chlorine and chloramine to make water safe for fish, but can also include medications. However, most of these chemicals are not food-grade and cannot be ingested safely for certain. Some fish keepers use alternatives, like ascorbic acid, as a dechlorinator, but this takes some special measuring.

One product you might not consider a threat to plants is aquarium salt. Most plants cannot physiologically process salt and may start to die as a result. You should never use saltwater for a garden if you keep a marine tank.

⚠️ From my experience: The two setups I always warn people about are saltwater/reef tanks and African cichlid tanks. Reef tanks have obvious salt issues, but cichlid tanks also tend to run high pH and sometimes have added salt. both can damage or kill garden plants. Stick with a standard freshwater community tank and you’ll be fine.

If the tank has been medicated in the past or is currently being medicated, you should also not use the water on your garden.

In general, you should avoid using chemically treated fish tank water on plants you intend to eat.

Does pH matter?

So far, we have not discussed pH. Freshwater aquariums typically have a neutral pH of around 7.0, but some blackwater or cichlid tanks might have well above or below that. Most plants thrive in the neutral zone, though some species prefer acidic or basic conditions respectively.

Another important parameter to consider is alkalinity, or the ability of water to buffer changes in pH. This parameter is rarely discussed in freshwater aquariums, with general hardness being a bigger concern. However, a high alkalinity can also impede plant growth and start to affect the effectiveness of pesticides and other enhancers.

Aquaponics

If you’re serious about using your fish tank’s water to facilitate your plant growth, you might be interested in the greater field of aquaponics.

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This takes growing plants with fish tank water to a whole other level. Simply put, aquaponics is sustainable farming using a closed-loop system that is dependent on the nitrogen cycle: fish create waste and the plants uptake the nutrients. Plants are grown directly in the water for easy nutrient uptake without the need for soil.

Some plants that can be grown in these systems include lettuce, tomatoes, peppers, and herbs.

Can I use fish tank water to water my plants?

Yes! Freshwater fish tank water is a great source of nutrients required for healthy plant growth, like nitrates. However, too much watering with aquarium water can overload your plants with nutrients, which can also be detrimental.

Is aquarium water conditioner good for plants?

If you’re planning on eating the foods you’re growing, you should not use chemically treated fish tank water. This is because these chemicals have not been evaluated for consumption. Instead, alternatives, like ascorbic acid, could be used to neutralize chlorine for fish.

Is fish tank water good for gardens?

Yes, you can use fish tank water on indoor and outdoor plants. Make sure to avoid plants that you will eat as aquarium water is often treated with various chemicals, like dechlorinator.

Conclusion

If you love aquariums and gardening, then there are many reasons to start using your tank water to feed your plants! Aquarium water is packed with important nutrients, like nitrate, that can fertilize your plants as needed. Avoid using water that has been chemically treated on edible plants, but save your water change leftovers for later use.

🌿 Want to learn more? This article is part of our complete Planted Tank & Aquascaping Guide. your ultimate resource for aquarium plants, aquascaping styles, substrates, and more.
March 24, 2024

Severum Tank Mates: My 15 Picks After Years in the Aquarium Trade

Severums have a well-earned reputation as gentle giants in the cichlid world. and having cared for them at local fish stores over the years, I’d say that’s accurate. They’re surprisingly peaceful for a cichlid of their size, which opens up a lot of stocking options. But you still need to choose carefully: the wrong tank mate can stress them out or end up as a meal. Here are my picks for the best severum tank mates, plus the ones I’d steer clear of.

Key Takeaways

Severums are fairly peaceful cichlids that can be kept with a variety of other tropical fish species.
The best severum cichlid tank mates are other medium to large fish that prefer a similar water temperature and parameters.
The severum cichlid is omnivorous, so they are not safe to keep with nano fish like neon tetras.
Severums will also eat live plants and invertebrates like shrimp.

The Top 15 Severum Tank Mates

Are you ready to meet 15 suitable tank mates for your severum cichlid? Read on to find the perfect match for your severum community! Here’s a video from our official Yo u Tube Channel. If you like our videos, subscribe to our channel.

Expert Take

After 25+ years in the hobby and time caring for them at the stores I managed, I can tell you that severum keepers who give this fish the right setup rarely regret it. I’ve seen severum pairs hold a 75-gallon tank for years, the fish rewards the setup you give it. Severums are one of the most underrated cichlids in the hobby. They’re big, personable, and surprisingly peaceful for a cichlid their size, unless they’re breeding, at which point the entire tank becomes off-limits to other fish. The real compatibility challenge isn’t aggression, it’s size. Severums reach 8–10 inches (20–25 cm), and most ‘peaceful’ small fish simply disappear into them over time. — Mark Valderrama, AquariumStoreDepot

Quick-Reference Comparison Table

Species	Adult Size	Min Tank	Ease	Compatibility
Silver Dollars	6 inches	75 gallons	7/10	High
Oscars	10-14 inches	75+ gallons	7/10	High
Dension Barbs	4 inches	55 gallons	7/10	High
Pearl Gourami	4-5 inches	30-40 gallons	7/10	High
Medium to large plecos	4 – 12 inches	Species-dependent, medium-sized species will thrive in a 55-gallon+ aquarium	7/10	High
Angelfish	6 inches	40 gallons	7/10	High
Blue Gourami	5-6 inches	35 gallons	7/10	High
Geophagus	5-12 inches	Species dependent, 55 gallons for smaller species	7/10	High
Larger Rainbowfish	4-6 inches	55 gallons	7/10	High
Uaru Cichlid	10-12 inches	75 gallons	7/10	High
Kissing Gourami	8-10 inches	50 gallons	7/10	High
Electric Blue Acara	6-7 inches	40 gallons	7/10	High
Salvini Cichlid	Up to 6 inches	55 gallons	7/10	High
Bolivian Rams	3 inches	30 gallons	7/10	High

1. Other Severums

Before we start getting into other species, let’s discuss the option of keeping multiple severums together in the same tank. Now, these fish don’t need to be kept in schools, and you can keep just a single fish, but many aquarists have kept them together without trouble.

Of course, severums are large fish, so you’ll probably need a tank that holds a few hundred gallons to keep a group into adulthood. Housing four or more fish together may also help to limit aggression.

They can be semi-aggressive toward each other, so it’s a good idea to buy them young and add them to the tank at the same time. Choosing individuals of different breeds may also help to prevent aggression, although you’ll probably want to prevent them from hybridizing if you are considering breeding them.

2. Silver Dollars

Ease: 7/10. Good choice with a few conditions to watch.

Scientific name: Metynnis argenteus
Origin: South America
Adult size: 6 inches
Minimum tank size: 75 gallons
pH: 6-7
Temperature: 75-82°F
Temperament: Peaceful

The silver dollar is a peaceful South American schooling fish with an accurate name. These rounded fish are mostly silvery in color, although they may have some orange color on their anal fins.

Silver dollars tend to hang out in the middle and upper layers of the tank where their high activity levels add a lot of movement. However, these fish do best in groups of about 5 or more, so you’ll need a large aquarium to house them with your severums.

3. Oscars

Ease: 7/10. Good choice with a few conditions to watch.

Scientific name: Astronotus ocellatus
Origin: South America
Adult size: 10-14 inches
Minimum tank size: 75+ gallons
pH: 6-7.5
Temperature: 68-82°F
Temperament: Semi-aggressive

Oscars can make great severum tank mates, although a lot depends on their individual personalities. Like the severum cichlid, these large South American cichlids are available in several awesome color patterns, and they generally get along well with tank mates that are too large to fit in their mouths!

Oscars are pretty easy to care for, although they are carnivorous fish that need a balanced diet that includes some meaty foods like earthworms. These fish also grow even larger than the severum cichlid, so this pairing will not work in anything less than a 75-gallon tank.

4. Dension Barbs

Ease: 7/10. Good choice with a few conditions to watch.

Scientific name: Sahyadria denisonii
Origin: India
Adult size: 4 inches
Minimum tank size: 55 gallons
pH: 6.8-7.8
Temperature: 60-77°F
Temperament: Peaceful

The denison barb (also known as the roseline shark) is a great choice for aquarists who want a colorful active tank mate for their severum cichlid.

However, these fish prefer cooler water temperatures than many other tropical species, so you’d need to maintain your water temperatures around the mid-70s Fahrenheit to keep everyone comfortable. Denison barbs do best in a large school, so buy a group of at least 6 individuals.

5. Pearl Gourami

Ease: 7/10. Good choice with a few conditions to watch.

Scientific name: Trichpodus leerii
Origin: Southeast Asia
Adult size: 4-5 inches
Minimum tank size: 30-40 gallons
pH: 6-7
Temperature: 75-82°F
Temperament: Peaceful

The pearl gourami is a peaceful, docile fish that enjoys similar water conditions to the severum cichlid. These tropical fish do well in community tanks, although you should keep four or more in the same tank.

These gouramis have a reddish body covered in beautiful pearly spots and a dark horizontal line from their eye to their tail. There pelvic fins are modified into interesting feelers that they move around to explore their environment, making this a fascinating fish to watch.

Hard Rule: Never add fish under 4 inches (10 cm) to a severum tank. A 10-inch severum doesn’t need to be aggressive to eat a tetra, it’s just what happens. Keep companions at a minimum of half the severum’s body length.

6. Medium to large plecos

Ease: 7/10. Good choice with a few conditions to watch.

Scientific name: Hypostomus spp. Parancistrus spp. Ancistrus sp. etc.
Origin: South America
Adult size: 4 – 12 inches
Minimum tank size: Species-dependent, medium-sized species will thrive in a 55-gallon+ aquarium
pH: Neutral to slightly basic conditions are suitable for many species
Temperature: 75-80°F is suitable for many species
Temperament: Generally peaceful but can be territorial toward their own kind

Plecostomus catfish are laid-back bottom feeders that spend most of their time hanging out on the bottom of the tank or sucking onto rocks and driftwood. These cleaner fish are not aggressive, although they can hold their own against more boisterous tank mates.

Many species will make excellent tank mates for severums, although it’s important to research their needs carefully before you buy. Some pleco species grow surprisingly large, while others require strong water flow or high temperatures

Check out my guide to 15 pl e co fish species to learn about some of the best types in the hobby!

7. Angelfish

Ease: 7/10. Good choice with a few conditions to watch.

Scientific name: Pterophyllum spp.
Origin: South America
Adult size: 6 inches
Minimum tank size: 40 gallons
pH: 6-7
Temperature: 75-82 °F
Temperament: Generally peaceful

Known for their distinctive body shape, freshwater angelfish are incredibly popular in the aquarium hobby. These medium-sized South American cichlids are good tank mates for severums and many other peaceful community fish.

Angelfish are available in a few different species, including the larger altum angelfish (Pterophyllum altum) and the rarer Leopold’s angelfish (P. leopoldi). The regular freshwater angelfish (P. scalare) is also available in many stunning color morphs.

8. Blue Gourami

Ease: 7/10. Good choice with a few conditions to watch.

Scientific name: Trichopodus trichopterus
Origin: Southeast Asia
Adult size: 5-6 inches
Minimum tank size: 35 gallons
pH: 6-8
Temperature: 75-86°F
Temperament: Semi-aggressive

The blue gourami (also known as the three-spot gourami) is one of the most beautiful gourami species in the hobby, and it can make a good tank mate for severum cichlids.

However, blue gouramis are also one of the more aggressive gouramis, so you’ll need to consider the safety of any other tank mates you might want to keep.

9. Geophagus

Ease: 7/10. Good choice with a few conditions to watch.

Scientific name: Geophagus spp.
Origin: Amazon River Basin, South America
Adult size: 5-12 inches
Minimum tank size: Species dependent, 55 gallons for smaller species
pH: Species dependent, slightly acidic to slightly basic
Temperature: Species dependent, generally upper 70s and lower 80s Fahrenheit
Temperament: Peaceful and social

Geophagus cichlids are also known as earth-eaters for their habit of searching for sucking in sand in search of food. This diverse group of South American cichlids includes many species that will work with severums, although it’s important to research the specific water parameter and tank size needs of each type before adding it to your tank.

It’s also important to house these fish in an aquarium with a sandy substrate to allow for natural foraging behaviors. The various geophagus cichlids inhabit diverse habitats, including still waters and fast-flowing rivers, so select species that will enjoy the same conditions as your severum cichlid.

10. Larger Rainbowfish

Ease: 7/10. Good choice with a few conditions to watch.

Scientific name: Melanotaenia spp. Glossolepis etc.
Origin: Southeast Asia and Australasia
Adult size: 4-6 inches
Minimum tank size: 55 gallons
pH: 7-8
Temperature: 74-78°F
Temperament: Peaceful

Larger rainbowfish species, like the boesemani and red rainbowfish, can make excellent tank mates for severum cichlids, especially if you are looking for large and colorful species that swim actively in the open water.

However, it’s important to consider their water chemistry preferences when housing them with severum cichlids and South American species. These peaceful fish prefer temperatures in the mid-70s Fahrenheit and neutral to slightly basic water chemistry, so they have a fairly narrow parameter overlap with severums.

11. Uaru Cichlid

Ease: 7/10. Good choice with a few conditions to watch.

Scientific name: Uaru amphiacanthoides
Origin: South America
Adult size: 10-12 inches
Minimum tank size: 75 gallons
pH: 6-7
Temperature: 82-86°F
Temperament: Peaceful

The Uaru is a large South American cichlid with attractive but neutral body colors. They are identified by the large black blotch on either side of their body and by their bright red or yellow eyes.

Uaru cichlids are very peaceful and make excellent severum cichlid tank mates, although they require pretty warm water. A tropical aquarium with temperatures in the lower 80s Fahrenheit will be ideal for this tank mate combination.

12. Kissing Gourami

Ease: 7/10. Good choice with a few conditions to watch.

Scientific name: Helostoma temminkii
Origin: Southeast Asia
Adult size: 8-10 inches
Minimum tank size: 50 gallons
pH: 6-8
Temperature: 72-86°F
Temperament: Semi-aggressive

The kissing gourami is a fascinating freshwater species known for its habit of locking lips with its own kind. These filter-feeding fish are fairly peaceful, and their specialized diet means they can be kept with much smaller tank mates.

13. Electric Blue Acara

Ease: 7/10. Good choice with a few conditions to watch.

Scientific name: Most likely to be a hybrid
Origin: South American ancestry
Adult size: 6-7 inches
Minimum tank size: 40 gallons
pH: 6-7
Temperature: 74-82°F
Temperament: Semi-aggressive

The electric blue acara is a stunning South American cichlid that is most likely to be a hybrid of two or more wild species. These medium-sized freshwater fish are excellent tankmates for severums because they show little aggression and thrive in the same water conditions.

🏆 My top pick: After keeping and recommending these pairings over the years: out of all 15 options on this list, the Electric Blue Acara is the one I’d recommend first. The temperament match with severums is excellent. neither fish is looking for a fight. and their water parameter requirements line up well. A great pairing.

14. Salvini Cichlid

Ease: 7/10. Good choice with a few conditions to watch.

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Scientific name: Cichlasoma salvini
Origin: Central America from Mexico to Belize
Adult size: Up to 6 inches
Minimum tank size: 55 gallons
pH: 6.5-8
Temperature: 72-79°F
Temperament: Aggressive

The Salvini cichlid is one of the most gorgeous cichlid species in the aquarium world. Unfortunately, they tend to show aggressive breeding behavior, although large severums can generally hold their own against these stunning fish if you provide a suitable environment.

You can minimize aggressive behavior by keeping a single fish (salvini cichlid pairs can be highly aggressive), providing plenty of space in a large aquarium, and by providing plenty of caves and other hiding spots. Keep an eye on their behavior and be prepared to rehome them if you notice serious aggressive behavior.

15. Bolivian Rams

Ease: 7/10. Good choice with a few conditions to watch.

Scientific name: Mikrogeophagus altispinosus
Origin: South America
Adult size: 3 inches
Minimum tank size: 30 gallons
pH: 6-7.5
Temperature: 75-82°F
Temperament: Peaceful

Bolivian rams are beautiful severum cichlid companions for more experienced fishkeepers. Just keep in mind that rams are dwarf cichlids, so it may be risky to add young specimens to a tank with full-grown severums that are large enough to swallow them!

Bolivian rams are generally very peaceful and tend to hang out at the bottom of the tank. These fish can also be kept in aquariums as small as 30 gallons, so it is possible to house several individuals in a larger tank.

Fish To Avoid

While severums get along with many other freshwater fish species, there are a few species that you should definitely avoid. Here are four tank mates that are not recommended for adult severum cichlids:

⚠️ In my experience managing fish stores for years and keeping severums myself, the two mistakes I see most often: choosing fish that are too small (severums will bully or eat them once they’re fully grown) or too aggressive (severums are peaceful by cichlid standards and will get stressed by constant harassment). Size and temperament matching is everything with this species.

1. Dwarf Gourami

Large gouramis, like the pearl and kissing gouramis, are appropriate tank mates for severums, but smaller species, like honey and dwarf gouramis, are riskier. I would avoid keeping dwarf gouramis with larger cichlid species.

2. Smaller Tetras

Some fish keepers have success keeping severums with larger-bodied species like the black skirt tetra, although small schooling fish are generally not a good idea. You should definitely avoid small species like neon and ember tetras.

3. Highly aggressive fish

Despite their size, severum cichlids can be vulnerable to attacks from aggressive fish. It’s best to avoid highly aggressive species like wolf cichlids, although some fishkeepers have success with aggressive species like Jack Dempseys and the blood parrot cichlid.

Be prepared to rehome any fish that don’t get along with your severums as fights and aggressive behaviors can result in serious injuries for one or both fish.

4. African Cichlids

It’s generally a bad idea to mix African cichlids with severums. Rift Valley cichlids from East Africa require really hard, basic water to survive, while severums prefer neutral or even slightly acidic conditions.

Aggression and compatibility can also be a problem, so if you do try this pairing, stick to more peaceful species like electric yellow labs.

Care Basics

Also known as banded cichlids or ‘poor man’s discus,’ the severum cichlid (Heros sp.) is a large but peaceful South American fish from the cichlid family. There are many different varieties in the aquarium trade, including the green severum, the gold severum, and various other species in the Heros genus.

Severums can grow to about a foot long out in the wild, but they usually max out at less than ten inches in the home aquarium. They are easy to care for, although they require a large aquarium of at least 55 gallons.

Diet

Severums are omnivorous fish that require a varied diet. High-quality pellets are a good staple diet but you should include frozen foods like brine shrimp, bloodworms, and plant matter like blanched vegetables to keep your fish healthy and encourage breeding behavior.

Recommended Water Parameters

Temperature: 75-84°F
pH: 6-7.5
Water hardness: 4-6dH

There’s much more to learn about severum cichlid care! Go ahead and check out my in-depth severum cichlid care guide for much more on these awesome fish.

Community Aquarium Setup Tips

Aquarium Size

A 55-gallon tank is suitable for growing out young fish or keeping a single severum cichlid. However, larger fish will do better in a 75-gallon tank, and you’ll need even more space if you’re adding a few tank mates.

Great Beginner SW Tank

Aqueon 60 Gallon Breeder

This new 60 gallon breeder by Aqueon has the length and width of a 75 gallon tank, but at a shorter height. This is the most economical and effective 4 foot gallon tank for the saltwater hobby now.

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A 125+ gallon setup should provide adequate space for a severum cichlid community with a few other medium/large fish, although a bigger tank is always better!

Decor and Planting

The ideal layout for the severum cichlid includes plenty of driftwood over a sandy substrate. Unfortunately, these omnivorous cichlids will eat live plants, so it’s generally not a good idea to keep these partly vegetarian fish in planted tanks. However, you could try some tough species like Java fern if you’re not too worried about them getting chewed on.

Characteristics of Suitable Companion species

This species can be housed with many other medium to large freshwater aquarium fish. However, it’s important to select tank mates that thrive in the same water conditions as the severum cichlid.

Severums are not particularly aggressive, although they can hold their own with slightly more aggressive and boisterous species. Small, slow-moving fish are a risky choice because severums are omnivorous.

How big of a tank do Severums need?

The minimum tank size for severum cichlids is 55 gallons. However, breeding pairs will require a 75-gallon tank, and you may need to go even larger when keeping multiple fish or adding a few medium to large tank mates.

Are Severums aggressive?

Severums are relatively peaceful cichlids, making them an excellent choice for a larger community tank. However, some species are more aggressive than others and each specimen has its own personality.

They may also become aggressive when breeding, so these fish are generally classified as semi-aggressive.

Will Severums eat neon tetras?

Severums are omnivorous and generally feed on plant material and invertebrates. However, a larger specimen will feed on other fish if they are slow enough to catch and small enough to swallow. Keeping the severum cichlid with neon tetras and other small schooling species is not recommended.

Can you keep a single Severum?

Severums can be kept on their own or in small groups. Some sources indicate that single fish may become more aggressive without the company of their own kind, although many aquarists have no problems keeping these fish on their own.

Can a severum live with African cichlids?

Severums are not ideal tank mates for African cichlids from Lake Malawi, Victoria, and Tanganyika. Those fish are adapted to water with high pH and mineral content, whereas severums prefer soft water with a pH closer to neutral.

South and Central American cichlid species or West African cichlids like the kribensis are usually a better match on water parameters.

Mark’s Pick: Having kept and sold these fish for years, I consistently come back to the same recommendation: large, peaceful cichlids or bottom dwellers, large plecos, geophagus, or festivum cichlids. These fish share the severum’s water preferences and can hold their own as the severum grows.

Who Is This Setup Right For?

Good Fit If:

You have a 75+ gallon tank for a pair, 55 gallons for a solo severum
You keep large, hardy fish that won’t be intimidated or eaten as the severum matures
You enjoy large cichlids with real personality and aren’t put off by breeding aggression
You keep South American biotope conditions, pH 6.0–7.5, moderate hardness

Avoid If:

You have small fish under 4 inches (10 cm), they will be eaten as the severum grows
You want to pair severums in anything under 75 gallons, breeding aggression requires space
You keep delicate, nervous fish that don’t handle the presence of large cichlids well
You want a peaceful community without any cichlid-level territorial behavior during breeding season

Final Thoughts

Careful consideration is necessary when choosing tank mates for freshwater fish – especially when cichlids are involved. Fortunately, the severum cichlid is a gentle giant of the fish keeping world, suitable for many different freshwater tank mates. I hope this guide to the 15 best severum cichlid tank mates has helped you narrow down your options and find the perfect companions for your severum!

Do you keep severums? Share your favorite tank mates in the comments below!

📘 Want to learn more? This article is part of our complete Freshwater Fish Guide. your ultimate resource for freshwater species, care tips, tank setup, and more.

March 23, 2024

Fish Tank Filter Not Working? My Troubleshooting Guide After 25 Years
Is your fish tank filter not working?

Aquarium filters are essential in this hobby, so when they stop working, you can expect some problems! But what should you do if your filter malfunctions? Well, don’t rush off to buy a new one too soon because there’s a good chance you can fix it yourself!

In this guide, I’m going to help you get your aquarium filter up and running again. We’ll start off with some pretty obvious stuff and progress to more technical issues, so read through until the end and you should have the solution you need.
Key Takeaways
- Aquarium filters can stop working for many different reasons, but it’s often possible to fix the problem at home.
- Start with the simplest solutions before taking drastic actions. Sometimes all you need to do is check your filter’s electrical plug.
- A lack of aquarium maintenance can cause various filter problems, so invest a little time every week or two to inspect and maintain your equipment.
- ELECTRICITY IS DANGEROUS. Unplug your filter before inspecting it and please leave electrical work to competent individuals.
Troubleshooting – First Steps and Clues

Are you sure it’s not working?

This may seem like a silly question, but some filters are almost completely silent so you really need to look or feel to know if they’re running. Look for water flow near the filter’s outflow to know if water is moving through the pump.

If you’re sure your filter is not running, it’s time to figure out why.

When did it stop working?

Doing a little detective work can help you figure out some potential causes of your fish tank filter not working.

Let’s take a look at a few scenarios:
- After a power outage: Some filters need to be primed each time you start them. So, if your power went out, you might be able to re-prime your filter and get it up and running again.
- After a power surge: Lightning strikes, tree falls, and power outages can all cause surges that could damage electrical equipment¹.
- Gradual loss of performance: If your filter has been weak or noisy for some time, it could be a sign of a clogged impeller or filter media. These problems tend to build up over time.
Fish Tank Filter Not Working – 5 Possible Causes

Finding the problem with your aquarium filtration system is much easier when you know where to look. Continue reading to discover five possible causes and what you can do to solve them.

1. Power Problems

Aquarium filters need electricity to run, so that’s the first place to look when your fish tank filter stops working. Before we go any further, I just want to remind you of something obvious: ELECTRICITY IS DANGEROUS. Please leave electrical work to trained professionals.

With that out of the way, let’s look at some safe tests that you can do.
- Check the power source
If your filter isn’t running at all, don’t be too quick to assume that the filter is the problem! The issue could also lie with your power supply, power strip, or any of the connections between your electrical panel and the filter itself.

Start by making sure the filter is plugged in at a power outlet. Some outlets have a dedicated on/off switch, so make sure that’s in the ‘on’ position.

If it’s definitely plugged in but still not running, your next step is to test the outlet. You can do this by unplugging the filter and plugging in a different electrical appliance like a lamp. If that doesn’t work either, your filter is probably not the problem.
- Check your power strip
Sometimes there’s nothing wrong with the power source or the filter. Your powerstrip might be faulty or need to be reset. Some power strips include a reset button that will need to be pressed after a power surge or overload.
- Inspect the cable
Electrical cables are pretty prone to damage, so it’s a good idea to visually inspect them for signs of wear or breaks. If you’re handy, you may be able to repair a worn cable yourself, but I recommend getting help from a pro if you’re not sure.
- Are you using a timer?
It’s best to set your aquarium lights on a timer to keep a regular day/night schedule. However, your fish tank filter should be set to run constantly.

It’s annoyingly easy to get your plugs mixed up during the aquarium cleaning process, and sometimes the solution is as simple as switching plugs! If this happens to you, consider putting a zip tie or some colored tape on your filter cable to help you identify it easily.

2. Clogged Filter

Your filter is designed to collect debris from the water, but sometimes, these waste particles build up to such an extent that they create blockages that prevent your filter from working properly.
- Rinse regularly
Many fish tank filters use a synthetic sponge material as a filtration media. These sponges do not need to be replaced until they begin to fall apart, although they do require regular maintenance to avoid blockages.

The dirt that collects in your aquarium filter media will reduce water flow and mechanical filtration, but you can avoid this by simply rinsing the sponge outside of your aquarium in some tank water. Avoid using chemicals or hot water when cleaning your sponge media as this can kill the good bacteria that are essential for proper filtration.

Check out my detailed guide to the aquarium cycle to learn more about beneficial bacteria and the nitrogen cycle.
- When to replace
Some filters are designed to use cartridges that must be replaced regularly. This type of media should be replaced at the intervals recommended by the manufacturer to avoid a reduced water flow rate. Filter floss is another filter media that clogs easily and will need to be replaced regularly.

3. Air Locks

Sometimes, air gets into the filter and causes an air lock which reduces your flow rate or even prevents your filter from moving water. This often happens when the filter intake is not positioned below the water’s surface, although it also occurs if you run an airstone near the intake. You may need to prime your filter to get it restarted, although the procedure will differ depending on the type of filter you have.
- Hang on back filters
Many hang-on-back (HOB) filters need to be primed before they can operate or they may be very noisy and fail to operate correctly. However, some models have self-priming technology.

To prime a HOB, simply fill the impeller chamber with water from the aquarium until it begins to flow through the outflow and back into the tank. Then, you can adjust the flow rate to suit your needs.
- Canister filters
Many canister filters have self-priming technology, but some must be manually primed using the built-in pump. You may also need to rock your canister filter back and forth or side to side to dislodge any air trapped in the impeller housing. These filters should be placed below your aquarium for best results.

4. Disrupted Water Flow

Each aquarium filter type works differently, but they are all designed to suck water from the aquarium and pass it through some sort of filter media. The obvious exceptions are sponge or under gravel filters that work with an air pump.

Your filtration system will not work properly if water can’t flow through the media as it should, so it’s important to inspect your filter and ensure that everything is clean and put together properly.
- Water intake obstructions
The water intake is a common source of problems since this is the first place where blockages can occur. Inspect the intake grid or tubes for obstructions like plant leaves or hiding snails.

Sometimes, the intake tube of your filter may become dislodged, which disrupts the flow of water through the system. Make sure this component is seated properly as it can make a huge difference.
- Flow valves and flow rate adjustment
Many modern aquarium filters come with an adjustable flow rate, so this is a good place to start if your filter just seems a little weak. Check out your user manual or look for a dial or lever to increase the flow rate.

Canister filters have valves on both the intake and output valves. Water will not be able to flow through the canister if either of these valves are shut, so make sure the tabs of each valve are in the open position, or at least open enough for water to pass through.
- Water level in the tank
Over time, water will evaporate from your aquarium, leading to a slow decrease in water level. If the level gets below your filter’s intake, the unit will begin to suck air, and it may overheat or malfunction. Keep your aquarium full with regular top-ups and water changes.

5. Filter Motor Problems
- Clogged impeller
Internal power filters, canister filters, and hang-on-back filters all have a part known as an impeller, and this is a very common cause of filter issues.

The filter impeller is the part of the pump that spins, creating a water current that sucks water through the filtration media and back into the tank. Sometimes, this crucial part becomes dislodged from its correct position or it may get clogged with gravel or wrapped up in fibers or hairs that prevent it from spinning.
- Impeller maintenance
You can usually access the impeller pretty easily without any special tools, but make sure the filter is unplugged before opening it up. Gently remove the impeller with your fingers or a pair of tweezers and clean it off, paying attention to the blades and the steel impeller shaft. You should also look for obstructions in the impeller housing and clean it out if necessary.
- Impeller replacement
You can often get your aquarium filter back up and running by simply cleaning out the impeller and housing, but eventually, you might need to replace some parts. Impellers don’t last forever, so order a replacement when yours becomes grooved, worn, or broken.

What To Do If You Can’t Fix It – 5 Helpful Tips

You’re going to need to take action if you’ve tried all the options listed above and you still can’t get your filter to run. Here’s what you should do:
- Aerate your aquarium water
Your aquarium is not going to crash instantly without a filter, although the situation can become more serious after a few hours.

In the meantime, use an air pump and air stone to oxygenate your aquarium water. This will help your fish breathe and supply dissolved oxygen to the beneficial bacteria that live within your substrate and on surfaces within the tank.
- Run a spare filter
I recommend keeping a cheap spare filter for this kind of situation, but it’s very important to use it correctly here. If you’ve got an idea of how aquarium cycling and the nitrogen cycle work, you’ll know that special bacteria live in the media in your filter and that it can take several weeks to build up a decent colony.

Put the media from your faulty filter into your spare until you can get a new filter or fit replacement parts. You may have to trim the old sponge down to size, but that shouldn’t be a problem. Bio balls and other media types can also be transferred to your spare filter if the design allows custom media.
- Buying replacement parts
You can usually buy replacement parts if you have a decent brand-name fish tank filter, although it may make more sense to buy a new filter in some cases. You can ask your local fish store to order replacement parts or simply purchase them online.
- What if you don’t have a spare filter?
It is possible to care for the beneficial bacteria in your old filter media, although it can get a little messy if the old media hasn’t been rinsed in a while. Gently remove the media and place it in the tank near an air stone to encourage some water movement through the media and keep the good bacteria oxygenated until you can get a new filter up and running.

Note that if you purchase the same filter to replace your broken one, you can swap the filter media into the new filter. This will help prevent losses in the bacteria colony as the colony will still function in the new filter.
- Running a second filter
Did you know that you can run two or even three filters in the same aquarium? Most aquarists will run a single powerful filter, although two smaller fish tank filters can provide adequate filtration while giving you that extra insurance in case one fails.

Understocking your tank and growing live plants are great ways to slow the build-up of nitrate levels in the long run, but you can also reduce your filtration needs by feeding your fish correctly. Uneaten food is a major cause of poor water quality.

Why isn’t my fish tank water filter working?

Fish tank filters don’t last forever, although you should get many years of use out of a quality product. The most common problems that affect aquarium filters are air locks, clogged media, clogged impellers, and power supply problems.

How do I know if my fish tank filter is broken?

Some fish tank filters are virtually silent, but all canister, hang on back, and internal power filters should create some flow from their outlet. Your filter is not working if it does not pump any water.

How do you unclog a fish tank filter?

Start by rinsing out your filtration media. I recommend rinsing your filter sponge and media in a separate container filled with aquarium water from a water change.

Some filter cartridges and floss cannot be reused once clogged, so remember to replace them on a regular basis. Your filter may have indicators that tell you when to service or replace media, but you can also look for guidance in your instruction manual or check with the manufacturer online.

How long can fish survive without a filter?

Your fish may survive hours, days, or weeks without a filter. it all depends on your aquarium size, fish species, stocking level, and water chemistry. You can keep your water safer for longer by running an airstone, reducing feeding, and by testing water parameters and performing water changes as necessary.

What to do if your fish filter stops working?

A malfunctioning filter will reduce water quality, so this is one problem you should attend to immediately. Take a few minutes to run through the solutions mentioned in this article, including checking the power supply and looking for obstructions and clogs.

If you can’t solve the problem, you’ll need to install a different filter. I recommend seeding the new filter media with bacteria from your old filter.

How do I know if my filter is working in my fish tank?

Adequate mechanical and biological filtration will keep your water clean and prevent odors. A working fish tank filter will suck water into its outtake tube and pump it back into the aquarium. This should create a gentle current that you can see, hear, or feel in the water.

Final Thoughts

Providing proper filtration is essential for maintaining a beautiful aquarium and healthy fish, so it can be pretty stressful when your equipment malfunctions. I hope the advice in this guide helps you fix your filter problems without ordering a replacement, but please keep safety in mind when inspecting electrical equipment.

🔧 Want to learn more? This article is part of our complete Aquarium Equipment & Gear Guide. your ultimate resource for filters, heaters, lights, pumps, tanks, and more.
March 17, 2024

Best Beginner Tropical Fish: My 11 Picks After 25 Years of Fishkeeping

I have been keeping tropical fish for over 25 years, and choosing the right beginner fish is something I feel strongly about. Most people walk into a pet store, pick something colorful, and end up with incompatible fish or species that outgrow their tank within a year. After keeping hundreds of species across freshwater setups from 5-gallon betta tanks to 125-gallon community builds, I have put together this list of 11 fish I would genuinely recommend to any first-time fish keeper.

The tank size is always the overlooked beginner mistake. Not the fish choice. The tank size.

A 10-gallon tank is not a starter tank. It is a nano tank. It is harder to keep stable than a 20 or 30 gallon, and most beginner fish recommendations assume you have at least 20 gallons to work with. If you are starting with a 5 or 10 gallon, your options narrow significantly. I will tell you which fish actually work in each size category, and I will be honest about which “beginner fish” are actually not beginner fish at all.

EXPERT TAKE | MARK VALDERRAMA

After 25 years in this hobby and time managing fish stores, the one thing I see damage beginners most is the neon tetra myth. Neon tetras are sold as the quintessential beginner fish everywhere. They are not. They are sensitive to ammonia spikes, do not tolerate an uncycled tank, and need an established aquarium to survive long term. A beginner who buys 6 neon tetras for their brand new tank and loses them within a week does not have a fish problem. They have a water quality problem. The fish everyone should actually start with: platies, zebra danios, or corydoras catfish. These tolerate the learning curve. Neons do not.

What Actually Makes a Fish “Beginner-Friendly”?

A true beginner fish has four qualities:

Tolerates imperfect water chemistry and minor ammonia spikes
Accepts a wide temperature range (not demanding about exact degrees)
Eats readily available foods (flakes, pellets, frozen) without special feeding requirements
Stays small enough for a reasonable starter tank (under 3 inches / 7.5 cm)

Goldfish fail this test immediately, they produce enormous amounts of waste, require cold water, and grow far larger than most people expect. Neon tetras fail it because of their sensitivity to water quality. Oscar fish fail it because they grow to 12 inches (30 cm) and need 75+ gallons.

The fish on this list pass the test. I have recommended every one of them to beginners over the years and seen them succeed.

Beginner Tropical Fish by Difficulty

TIER BREAKDOWN

Very Forgiving (start here): Zebra danios, Platies, Corydoras catfish (bronze/albino), Bristlenose pleco
Forgiving (good second step): Guppies, Mollies, Swordtails, Betta fish (solo), White cloud mountain minnows
Marketed as Beginner but Actually Intermediate: Neon tetras (need established tank), Goldfish (cold water, heavy waste, large), Oscars (outgrow most tanks fast), Angelfish (cichlid behavior, needs height)

Best Beginner Tropical Fish: Quick Comparison

Fish	Difficulty	Max Size	Min Tank	Key Trait
Zebra Danio	Very Easy	2 in (5 cm)	10 gal	Hardiest beginner fish; used in cycling
Platy	Very Easy	2.5 in (6.3 cm)	10 gal	Hardiest livebearer; best guppy alternative
Corydoras (Bronze/Albino)	Easy	2.5 in (6.3 cm)	20 gal	Best beginner bottom feeder; needs school of 6+
Betta Fish	Easy	2.5 in (6.3 cm)	5 gal	Solo only; stunning personality
Bristlenose Pleco	Easy	4–5 in (10–13 cm)	25 gal	Algae control; stays manageable size
Guppy	Easy	2 in (5 cm)	10 gal	Colorful; buy quality strains
Molly	Easy	3–4 in (7.5–10 cm)	20 gal	Robust; tolerates hard water well
Swordtail	Easy	4–5 in (10–13 cm)	20 gal	Active; dramatic sword tail on males
White Cloud Mountain Minnow	Very Easy	1.5 in (3.8 cm)	10 gal	Cold tolerant; great nano fish
Neon Tetra	Intermediate	1.5 in (3.8 cm)	20 gal (established)	Not a true beginner fish; needs mature tank
Cherry Barb	Easy	2 in (5 cm)	20 gal	Hardy; peaceful barb that does not nip fins

11 Best Beginner Tropical Fish

1. Livebearers (Platies, Guppies, Mollies, Swordtails)

Scientific name: Poecilia and Xiphophorus spp.
Origin: North, Central, and South America
Size: 1–5 inches (2.5–12.7 cm) depending on species
Minimum tank size: 10 gallons for guppies/platies; 20+ gallons for mollies/swordtails
Temperament: Generally peaceful
Temperature: 68–82°F (20–28°C)
pH: 7.0–8.2

Livebearers are the most beginner-forgiving fish group in the freshwater hobby. They tolerate a wide range of water conditions, accept virtually any food, and reproduce readily if you have both sexes.

My personal recommendation within this group: platies. Guppies and mollies have been overbred to the point where store-bought specimens are often weaker and more disease-prone than they should be. Platies have held up much better. They are genuinely hardy, healthier as a group, and come in a great range of colors. If you are choosing your first livebearer, start with platies.

One thing to know: if you have males and females together, they will breed. Constantly. If you do not want a population explosion, keep only males (particularly with guppies) or only females.

2. Betta Fish (Betta splendens)

Scientific name: Betta splendens
Origin: Thailand
Size: 2–2.5 inches (5–6.3 cm)
Minimum tank size: 5 gallons (10+ preferred)
Temperament: Aggressive toward other bettas and some tankmates
Temperature: 76–82°F (24–28°C)
pH: 6.5–7.5

Bettas are showpiece fish. The personality, the flowing fins, the territorial behavior when it sees its own reflection, bettas are one of the most interactive fish you can keep. They come in an extraordinary variety of fin types and colors.

What people get wrong: bettas are often kept in bowls or vases, which is inadequate. They need a filtered, heated tank. A 5-gallon is the absolute minimum. A 10-gallon gives them room to behave naturally and makes water quality much easier to maintain. Males must be kept alone or with very carefully selected tankmates (no fin-nippers, no other bettas). Females can sometimes be kept in groups (“sororities”) but it requires space, dense planting, and careful monitoring.

Bettas are easy to keep well, but not easy to keep lazily. Give them the right setup from the start and they are genuinely rewarding fish that can live 3–5 years.

3. Zebra Danio (Danio rerio)

Scientific name: Danio rerio
Origin: South Asia
Size: Up to 2 inches (5 cm)
Minimum tank size: 10 gallons
Temperament: Active and peaceful; best in groups of 6+
Temperature: 64–77°F (18–25°C)
pH: 6.5–7.5

Zebra danios are the fish I recommend to beginners before any others. They are so hardy that they are used by fish scientists as model organisms. They tolerate temperature fluctuations, pH variability, and water chemistry imperfections that would kill more sensitive species. They are also incredibly active and entertaining, a school of 8–10 zebra danios darting around a tank is genuinely fun to watch.

Keep them in groups of at least 6. They are schooling fish and become stressed and less active when kept in small numbers. They are not fussy about food, flakes, micro pellets, frozen daphnia, anything works. The classic beginner fish, and for once, the recommendation actually makes sense.

4. Corydoras Catfish (Corydoras aeneus, C. paleatus)

Scientific name: Corydoras aeneus (bronze cory), C. paleatus (peppered cory)
Origin: South America
Size: 2–2.5 inches (5–6.3 cm)
Minimum tank size: 20 gallons
Temperament: Peaceful; active bottom dwellers
Temperature: 72–79°F (22–26°C)
pH: 6.0–7.5

Corydoras are the best beginner bottom-feeder and one of the most entertaining fish in the hobby. They school on the substrate, forage constantly, and interact with each other in ways that are genuinely fun to watch. Bronze corys and albino corys are the most beginner-friendly, they are hardy, widely available, and inexpensive.

The critical rule: keep corydoras in groups of at least 6. They are shoaling fish. A single cory, or even a pair, will be stressed and inactive. Six or more and they become a completely different fish, active, confident, constantly busy. Use soft, rounded substrate. Corys forage with their barbels (whiskers) and sharp gravel will damage them over time.

5. Bristlenose Pleco (Ancistrus sp.)

Scientific name: Ancistrus sp.
Origin: South America
Size: 4–5 inches (10–13 cm)
Minimum tank size: 25 gallons
Temperament: Peaceful; males territorial with other males
Temperature: 72–82°F (22–28°C)
pH: 6.5–7.5

The bristlenose pleco is the pleco for community tanks. Unlike common plecos that grow to 18 inches (46 cm), bristlenoses stay under 5 inches (13 cm) and are manageable for life in a standard tank. They eat algae, leftover food, and supplement well with vegetables (zucchini, cucumber) and algae wafers.

The most common mistake: buying a common pleco (Pterygoplichthys pardalis) instead of a bristlenose because it “looks the same” as a juvenile. Common plecos grow enormous. Bristlenose plecos do not. Check the label. If it says “pleco” without a specific species name, ask.

6. Cherry Barb (Puntius titteya)

Scientific name: Puntius titteya
Origin: Sri Lanka
Size: 2 inches (5 cm)
Minimum tank size: 20 gallons
Temperament: Peaceful; best in groups of 6+
Temperature: 73–81°F (23–27°C)
pH: 6.0–7.5

Cherry barbs are the barb for community tanks. Unlike tiger barbs, which are notorious fin nippers, cherry barbs are genuinely peaceful. Males develop a striking cherry-red coloration when in breeding condition. They are active, hardy, and do well with a wide variety of tankmates including bettas (with adequate space and planting). A great choice for someone who wants color in a peaceful community tank.

7. White Cloud Mountain Minnow (Tanichthys albonubes)

Scientific name: Tanichthys albonubes
Origin: China (White Cloud Mountain)
Size: 1.5 inches (3.8 cm)
Minimum tank size: 10 gallons
Temperament: Very peaceful; active schooling fish
Temperature: 57–72°F (14–22°C), cold tolerant
pH: 6.0–8.0

White cloud mountain minnows are an underrated beginner fish. They are extremely hardy, peaceful, and can tolerate temperatures down into the 50s°F (around 14°C), meaning they can be kept without a heater in a room-temperature environment in many climates. This makes them ideal for people who want a fish tank without the expense of a heater, or for outdoor pond use in moderate climates.

They are small, active schooling fish that look best in groups of 8 or more. The red and silver coloration on males is genuinely attractive under good lighting. Often overlooked in favor of neons, but honestly more appropriate for true beginners.

8. Dwarf Gourami (Trichogaster lalius)

Scientific name: Trichogaster lalius
Origin: India, Bangladesh
Size: 2 inches (5 cm)
Minimum tank size: 10 gallons
Temperament: Generally peaceful; males can be territorial
Temperature: 72–82°F (22–28°C)
pH: 6.0–7.5

Dwarf gouramis are beautiful labyrinth fish that breathe air from the surface in addition to using their gills. They come in striking color forms including flame (red-orange), neon blue, and powder blue. They are relatively peaceful and work well in community tanks with peaceful tankmates.

One honest caveat: dwarf gouramis have been affected by Dwarf Gourami Iridovirus (DGIV), a viral disease that is widespread in farm-raised specimens from certain suppliers. There is no cure and infected fish waste away over time. Buy from reputable sources and avoid fish that look thin or have sunken bellies. This is the one health risk specific to this species that beginners should know about upfront.

9. Harlequin Rasbora (Trigonostigma heteromorpha)

Scientific name: Trigonostigma heteromorpha
Origin: Southeast Asia
Size: 2 inches (5 cm)
Minimum tank size: 20 gallons
Temperament: Very peaceful; schooling fish
Temperature: 72–82°F (22–28°C)
pH: 6.0–7.5

Harlequin rasboras are one of the best schooling fish for community tanks. The orange-copper body with a distinctive black triangular patch is striking in groups, and they are genuinely peaceful with virtually every community fish. They are not as sensitive as neon tetras and handle the minor water quality variations of a beginner’s tank much better.

Keep them in groups of at least 8, the schooling behavior is the whole point. In a group they move together, flash their colors when light catches them, and create the kind of dynamic display that makes a community tank worth watching.

10. Cory Catfish (Sterbai Corydoras), for warmer tanks

Scientific name: Corydoras sterbai
Origin: Brazil, Bolivia
Size: 2.5 inches (6.3 cm)
Minimum tank size: 20 gallons
Temperament: Peaceful schooling bottom feeder
Temperature: 77–86°F (25–30°C)
pH: 6.0–7.5

Sterbai corydoras are specifically recommended for warmer community tanks (discus tanks, betta tanks kept at higher temperatures) because they tolerate the heat that would stress most corydoras species. The white-spotted pattern on a dark body is striking. Same care principles as bronze corys, keep in groups of 6+, soft substrate, peaceful tankmates.

11. Neon Tetra (Paracheirodon innesi), an honest assessment

Scientific name: Paracheirodon innesi
Origin: South America
Size: 1.5 inches (3.8 cm)
Minimum tank size: 20 gallons (established, not new)
Temperament: Peaceful schooling fish
Temperature: 70–81°F (21–27°C)
pH: 6.0–7.0

I am putting neon tetras last on this list deliberately. They are the most recommended beginner fish in the hobby, and they die more than almost anything else in beginner tanks. The truth is, neon tetras need an established, cycled aquarium with stable water chemistry. They do not tolerate ammonia spikes. They do not tolerate pH swings. In a brand new tank with a beginner still learning water chemistry management, neon tetras will die.

If your tank has been running for three to six months with stable parameters, by all means add neon tetras. They are beautiful in groups of 10 or more. But do not make them your first fish. Make them your reward fish, once you have proven to yourself that you can maintain stable water conditions. Start with danios or platies, get comfortable with the hobby, then add neons to a mature established tank.

Mark’s Pick: Best First Fish for New Hobbyists

MARK’S PICK

Zebra danios in a 20-gallon tank. Eight of them. Nothing else for the first few months. Danios will survive the learning curve, teach you what healthy active fish behavior looks like, and give you a chance to stabilize your water chemistry before you add anything more sensitive. Once your tank is established and your parameters are locked in, then you add the next species. This is how experienced fishkeepers start new tanks, and it works every time. Trying to stock a new tank with six different species on day one is how you end up with an expensive disaster and an empty tank.

Avoid These “Beginner Fish”, And Why

AVOID IF

Goldfish: They are not tropical fish. They are cold-water fish that produce extreme amounts of waste, grow to 12 inches (30 cm) or more in proper conditions, and cannot be mixed with tropical species that need warmer water. “My goldfish lived in a bowl for years”, that goldfish was surviving, not thriving.

Oscar fish: Sold as juveniles at 2 inches (5 cm), they grow to 12 inches (30 cm) and need a 75+ gallon tank as an adult. They will eat any fish that fits in their mouth and redecorate your tank by moving everything around. Not a beginner fish.

Neon tetras as a first fish: See above. They are sensitive to water quality and need an established tank. Make them a reward for successfully keeping your first fish.

Common plecos: They grow to 18 inches (46 cm) or more. Most people buy them as small juveniles and end up with a fish that outgrows everything within two years. Get a bristlenose pleco instead.

Any fish labeled “community” without a size check: Some “community fish” get to 8 inches and will eat their neighbors. Check adult size before buying, every time.

Closing Thoughts

The best beginner fish are ones that give you room to learn without punishing every mistake. Platies, danios, corydoras, these are fish that will be alive and active while you figure out water changes, feeding schedules, and parameter testing. That experience is what builds the skills you need for the more sensitive, more rewarding fish later on.

Get the foundation right, be patient, and the hobby opens up considerably. When you are ready to add fish to your tank, check the selection at Flip Aquatics or Dan’s Fish, both carry quality livestock and ship directly to your door.

March 16, 2024

Feeder Fish: My Honest Take After 25 Years of Using Them

I’ve used feeder fish in my own tanks over the years, mainly feeder guppies and goldfish, and I’ve formed a pretty clear opinion on them. Here’s the honest truth: feeder fish are a shortcut that comes with real consequences. Most hobbyists use them without understanding the disease risk they’re importing into their tank, and then they wonder why their predator fish keeps getting sick. This guide will give you the straight story on when feeders make sense, when they don’t, and how to use them without wrecking your tank.

Store-bought feeder fish are a disease vector first, a food source second. That’s the framing I want you to carry through this entire article.

Key Takeaways

Feeder fish from pet stores are kept in severely overcrowded, disease-prone conditions. Every batch you buy is a gamble on your tank’s health.
Guppies are the best feeder fish if you breed your own. Goldfish carry thiaminase and are the riskiest option long-term.
Gut-loading your feeders before use dramatically improves their nutritional value. A starving feeder fish is just an empty calorie with fins.
Frozen alternatives (silversides, smelt, tilapia strips) are safer and nearly as effective for most predatory fish.
Live feeders make sense as a transition tool, for wild-caught fish, or for enrichment. They are not a sustainable staple diet for most setups.

Expert Take | Mark Valderrama, AquariumStoreDepot

After 25 years in this hobby and time running aquarium retail stores, my honest take is this: feeder fish are useful in specific situations, but I see them cause way more problems than they solve. The disease risk from store-bought feeders is real and significant. If you are going to use them regularly, breed your own guppy colony. It takes a 10-gallon tank and a few months of patience, and it eliminates the biggest risk entirely. If you are not willing to do that, frozen alternatives are the safer call.

What Are Feeder Fish?

Feeder fish are any fish species bred or sold to serve as live prey for predatory aquarium fish. In practice, that means goldfish and guppies at most pet stores, though some bait shops also carry minnows, shiners, and bluegill. They are usually sold in bulk at under a dollar each and kept in bare, overcrowded tanks with minimal filtration and no quarantine.

That last point is the one that matters most. These fish are not pets. They receive no disease screening, no quarantine period, and minimal care. High turnover means sick fish are constantly cycling through. The conditions that make feeder tanks cheap to run are exactly the conditions that make them disease factories.

The Disease Risk Is the Whole Conversation

This is where most feeder fish articles gloss over the reality. I will not.

Store-bought feeder fish carry parasites, bacteria, and viral infections as a matter of routine. Ich is the most visible and common. Bacterial infections like columnaris travel with them. Internal parasites show no outward signs until they have already spread to your predator. And because you are introducing a live animal directly into your display tank, there is no quarantine step between “feeder tank at the store” and “your predator’s digestive tract.”

I’ve seen ich introduced to otherwise healthy tanks this way. I’ve watched a perfectly healthy oscar go downhill within two weeks of someone switching to store-bought goldfish feeders. The fish that seemed fine at the store were not fine.

The hard rule: if you are buying feeders from a store, quarantine them for 2 to 4 weeks before use. That’s a separate tank, proper filtration, and monitoring for disease. If you are not willing to do that, use frozen alternatives.

Types of Feeder Fish

ASD Feeder Fish Tiers

Tier 1 (Best): Home-bred guppies or platies. You control the diet, the water quality, and the disease risk. This is the only feeder approach I’d call genuinely safe.

Tier 2 (Acceptable): Store-bought guppies or minnows, quarantined for 2 to 4 weeks before use. More effort, but manageable.

Tier 3 (Use Sparingly): Store-bought goldfish. Highest disease risk, thiaminase problem, and they grow large if uneaten. I use these only as a last resort or for short-term transition feeding.

Bluegill

Bluegills (Lepomis macrochirus) are a common North American pond fish sometimes used as feeders for large predators like bass. They grow up to 12 inches (30 cm) and can be aggressive. Catching them from local waterways (where legal) introduces wild parasites and disease. They are rarely worth the trouble for aquarium use.

Goldfish

Feeder goldfish (Carassius auratus) are the most commonly sold feeder fish. They are available at almost every pet store, cheap, and accepted by most predatory fish. They are also the riskiest option for three specific reasons.

First, the disease issue. Goldfish feeder tanks are reliably overcrowded and under-maintained. Second, thiaminase. Goldfish contain thiaminase, an enzyme that breaks down vitamin B1 (thiamine). Regular, long-term feeding of goldfish to predatory fish can produce a thiamine deficiency that is difficult to diagnose and can eventually cause neurological issues and death. Third, size variability. Unless you can reliably identify goldfish varieties, you may end up with a fish that survives the feeding attempt and grows into a large, aggressive tank mate.

Guppies

Mark’s Pick

Guppies are my top recommendation for anyone serious about using live feeders. They stay under 1.5 inches (4 cm), breed constantly, and a small home colony in a 10-gallon tank can sustain most predatory fish without any store purchases. Set up the colony once, gut-load them with quality spirulina flake and frozen foods, and you have a steady, disease-controlled supply. That’s the right way to do this.

Store-bought guppies carry the same disease risks as goldfish, and like goldfish, many species contain thiaminase. This is less of a concern for short-term use, but matters if guppies become the primary diet.

Related alternatives in the same size range: mosquito fish (Gambusia, 2.8 inches / 7 cm) and minnows (2.5 inches / 6 cm). Both breed readily and can be kept in home colonies. Both also contain thiaminase.

Platies

Platies stay between 2 and 3 inches (5 to 7.5 cm), breed readily, and are not currently known to contain thiaminase. They are a solid second choice to guppies for home breeding. They are less commonly available as store-bought feeders, which means if you want platies, you are almost certainly raising them yourself. That is actually the ideal situation.

Feeder Fish vs. Frozen Alternatives: The Honest Comparison

Option	Disease Risk	Nutrition	Enrichment Value	Cost	Verdict
Store-bought goldfish	Very High	Poor + thiaminase	High	Low	Avoid long-term
Store-bought guppies (quarantined)	Moderate	Moderate	High	Low	Acceptable with quarantine
Home-bred guppies/platies (gut-loaded)	Very Low	Good	High	Very Low	Best option
Frozen silversides/smelt	None	Good	Low	Low	Excellent staple
Frozen tilapia strips	None	Good	None	Very Low	Budget staple

Gut-Loading: The Step Most Hobbyists Skip

Gut-loading means feeding your feeder fish a high-nutrition diet for 24 to 48 hours before offering them as prey. The predator eats the feeder, gets the contents of the feeder’s digestive tract, and benefits from a more nutritious meal. A starving feeder fish has almost no nutritional value. A well-fed one does.

For guppies and platies, gut-load with spirulina flake, frozen brine shrimp, or quality omnivore pellets. Skip the cheap flake food you’d normally use. You want the feeders to be as nutrient-dense as possible right before the feeding event.

When Feeder Fish Actually Make Sense

I am not anti-feeder fish. I am anti-using-them-without-understanding-the-tradeoffs. There are specific situations where live feeders are genuinely useful.

Transitioning wild-caught fish. Some fish collected from the wild will not recognize pellets or frozen food as food. Live feeders are often the only option to get them eating. Once established, most can be weaned onto prepared foods over weeks or months.

Stimulating a stubborn feeder. If you have a fish that has stopped eating, the movement of live prey can trigger a feeding response that frozen or prepared foods cannot. This is a short-term intervention, not a feeding strategy.

Enrichment for obligate predators. Large predatory fish kept in captivity can benefit from the mental stimulation of hunting. A biweekly live feeding event can support natural behavior. Just make sure the feeders come from your home colony.

Avoid If…

You are buying store-bought feeders without quarantining. The disease risk is too high to skip this step.
You are using goldfish as a regular staple. Long-term thiaminase exposure will cause thiamine deficiency in your predator.
Your predatory fish is eating well on prepared foods. Live feeders add risk without adding meaningful benefit in that situation.
You do not have a separate quarantine or colony tank. Without one, you cannot use live feeders safely.
You are using feeders for fish that can easily be conditioned to frozen or prepared foods. The transition effort is worth it.

How to Use Feeder Fish Safely

If you have decided to use feeder fish, here is how to do it without wrecking your tank.

Breed your own colony. A 10-gallon tank with a sponge filter, a group of guppies, and some floating plants will produce more feeders than most predatory fish need. Set it up once, feed the colony well, and you never buy store-bought feeders again.
Quarantine store-bought feeders. Two to four weeks minimum in a separate tank with clean water. Treat prophylactically for ich if you want to be thorough. Observe for visible signs of disease before using.
Gut-load 24 to 48 hours before feeding. High-quality spirulina flake, frozen brine shrimp, or quality pellets. Not the cheap stuff.
Feed once or twice a week maximum. Live feeders are a supplement, not a staple. The rest of the diet should be high-quality pellets, frozen foods, or other prepared options.
Remove uneaten feeders. If the predator is not hungry, take the feeders back out. Uneaten live fish in the display tank stress both fish and risk disease exposure even without being consumed.

FAQ

Can you feed your fish other fish?

Yes, many predatory fish eat other fish in the wild and can be fed live or frozen fish in captivity. The key is sourcing feeders safely and not relying on store-bought feeders as a long-term staple without proper quarantine.

What is the best feeder fish?

Home-bred guppies that have been gut-loaded with quality food. They are small, breed constantly, and when raised in clean water without exposure to store tank disease, they carry essentially no disease risk.

How often should you feed live fish?

Once or twice a week at most. Live feeders are a supplement, not a daily diet. Most predatory fish do better on a varied diet that includes high-quality prepared foods alongside occasional live or frozen options.

Are frozen alternatives as good as live feeders?

For nutritional purposes, frozen silversides, smelt, or tilapia strips are comparable and safer. The one thing frozen options cannot replicate is the enrichment value of hunting behavior. For most predatory fish, frozen options are the better daily choice, with live feeders reserved for occasional enrichment.

What is thiaminase and why does it matter?

Thiaminase is an enzyme found in many feeder fish species, including goldfish and guppies, that breaks down vitamin B1 (thiamine). When a predator regularly eats fish high in thiaminase, it can develop a thiamine deficiency over time, leading to neurological symptoms and eventually death. Platies are a notable exception and are not known to contain thiaminase, making them a safer long-term feeder option.

Closing Thoughts

Feeder fish are not inherently bad. The practice of keeping a home-bred guppy or platy colony, gut-loading them properly, and using them as an occasional supplement for a predatory fish is a legitimate and thoughtful approach. What is not a good approach is grabbing a bag of goldfish from a pet store feeder tank and dumping them in your oscar tank twice a week. That is how you import disease and create a thiamine deficiency you will struggle to diagnose.

If you keep predatory fish and want to use live feeders, build the colony. It takes one spare tank and a few months. The payoff is a disease-controlled, nutrient-rich food source you control completely. If you are not ready to make that investment, stick with frozen alternatives. They are safer, cheaper in the long run, and easier to manage.

Where to Find Quality Fish

If you are building a home feeder colony or stocking a predatory tank, these are the suppliers I recommend:

Flip Aquatics – Quality livestock with a 30-day guarantee. Good source for guppies, livebearers, and the predatory fish themselves.
Dan’s Fish – Another trusted online supplier for quality livestock and hard-to-find species.

March 13, 2024

Fish for a 55 Gallon Tank: My 21 Picks After Years in the Aquarium Trade

I’ve personally cared for nearly every fish on this list through my years working at local fish stores, so I can tell you firsthand which ones thrive in a 55-gallon setup and which ones cause problems. A 55-gallon tank is a fantastic size. It opens the door to impressive centerpiece fish and schooling communities alike, but that wide range of options is exactly where most fishkeepers go wrong. In this guide, I’ll share my top 21 picks, along with the stocking realities I see most often overlooked.

The 55-gallon is one of the most versatile tank sizes in the hobby. The challenge is not finding fish that fit. It’s choosing the right fish and building a coherent stocking plan instead of adding whatever catches your eye at the store.

Expert Take | Mark Valderrama, AquariumStoreDepot

A 55-gallon is where most hobbyists hit their stride. You have enough volume to keep water parameters stable, enough footprint (48 x 12 inches / 122 x 30 cm) to suit schooling fish and centerpiece species alike, and enough room to make stocking mistakes without immediate crisis. My advice: decide on your fish identity before you buy anything. A community schooling tank, a cichlid pair tank, and an African cichlid setup are completely different ecosystems. Trying to blend them is where most 55-gallon builds fall apart.

Key Takeaways

There are hundreds of species that work in a 55-gallon, but the best stocking plans are built around a single concept: community schooling, centerpiece species, cichlid setup, or predator tank.
The 48-inch footprint suits active schooling fish well. Species that need length to swim (large barbs, rainbowfish, denison barbs) do better in a 55 than a 40-gallon tall.
Inch-per-gallon is a myth. Do not use it. Bioload, waste output, and adult size are what matter. An oscar in a 55-gallon is at capacity. A school of neon tetras in the same tank is barely touching it.
Water parameters should be decided before fish are chosen, not after. Your local water chemistry determines which fish groups make sense for your setup.
The biggest stocking mistake: choosing fish for their appearance without researching adult size, temperament, and water requirements.

How to Stock a 55-Gallon Tank: Three Approaches That Work

ASD Stocking Tiers for a 55-Gallon Tank

Tier 1 (Beginner Friendly): Community schooling setup. Pick one species per level: a school of mid-level tetras or rasboras (10 to 15 fish), a bottom-dwelling group (6 to 8 corydoras), and a single centerpiece (a gourami, a small cichlid pair, or a betta). Easy to maintain, forgiving on water chemistry, looks excellent planted.

Tier 2 (Intermediate): Centerpiece species setup. Build the tank around one or two focal fish: a pair of angelfish, a single discus group, a pair of German blue rams in a planted soft-water tank. The centerpiece species determines your water parameters and tank mates.

Tier 3 (Dedicated): Single-species or species-group setup. African cichlid colonies, convict cichlid breeding pairs, or a single large predator (oscar, jack dempsey) in a species-only or dither-fish setup. High personality, high commitment, high reward.

Best Freshwater Fish For 55 Gallon Tanks

You can check out this video from our official YouTube Channel while following along on this blog post.

1. Freshwater Angelfish

Scientific name: Pterophyllum scalare
Care level: Easy
Minimum tank size: 40 gallons
Temperament: Generally peaceful but may be aggressive when breeding and will eat nano fish
Adult fish size: 6 inches (15 cm)
Origin: South America
Temperature: 75 to 82°F (24 to 28°C)
pH: 6 to 7
Diet: Omnivore
Swim Level: Mid-level
Type: Centerpiece

Freshwater angelfish are some of the most beautiful and elegant fish in the hobby and they thrive in a standard four-foot aquarium. These stunning South American cichlids are available in a range of different breeds, from pure white to black and multicolored.

A pair of angelfish in a 55-gallon planted tank is usually a great idea. Be aware that these fish can show territorial behavior around breeding time and they will snack on nano fish when they can catch them.

Mark’s Pick: Top Centerpiece for a 55-Gallon

If I were setting up a 55-gallon freshwater community tank today, angelfish would be my first choice. A pair in a well-planted setup is genuinely stunning. I’ve seen this work beautifully dozens of times through my years in the aquarium trade. Plan your community around them from the start and avoid adding nano fish as tank mates. Neon tetras and angelfish is a classic mistake. Angelfish are cichlids, and neons are angel food once the fish matures.

2. Congo Tetra

Scientific name: Phenacogrammus interruptus
Care level: Easy
Minimum tank size: 30 gallons
Temperament: Peaceful
Adult fish size: 2.5 to 3 inches (6 to 7.5 cm)
Origin: West Africa
Temperature: 73 to 82°F (23 to 28°C)
pH: 6 to 7.5
Diet: Omnivore
Swim Level: Middle and upper levels
Type: Schooling fish

The Congo tetra is a beautiful African schooling fish ideal for larger aquariums. Males are neon blue with an orange horizontal stripe and interesting pointed tail fins. Females have a classy gold and silvery color with shorter tails and more compact dorsal fins. A school of six or more will add variety and movement to the water column.

3. African Cichlids

Scientific name: Various
Care level: Moderate
Minimum tank size: Various
Temperament: Semi-aggressive
Adult fish size: 1.5 to 5 inches (4 to 13 cm)
Origin: East Africa
Temperature: 77 to 82°F (25 to 28°C)
pH: 7.5 to 9
Diet: Species dependent
Swim Level: Lower and middle levels
Type: Centerpiece fish

A four-foot tank is just large enough for an African cichlid setup, although it’s important to choose the right species to minimize territorial disputes and provide the hard, high-pH water these fish require. Smaller mbuna cichlids like yellow labs or shell dwellers are ideal for this tank size. You could also start a breeding group of a smaller peacock species.

4. Synodontis Catfish

Scientific name: Synodontis spp.
Care level: Easy to moderate
Minimum tank size: 30 to 50 gallons
Temperament: Peaceful / Semi-aggressive
Adult fish size: 4 to 8 inches (10 to 20 cm)
Origin: East Africa
Temperature: 74 to 82°F (23 to 28°C)
pH: 7.5 to 8.5
Diet: Omnivore
Swim Level: Bottom
Type: Bottom dweller

There are several species of Synodontis catfish available in the aquarium hobby, and these interesting fish are especially popular as bottom-dwelling tank mates in an African cichlid setup. They tolerate the hard, alkaline water that African cichlids require, which makes them one of the few reliable bottom-dweller options for that type of tank. Synodontis prefer the company of their own kind, so pick up a school of four or more.

5. Discus

Scientific name: Symphysodon discus
Care level: Advanced
Minimum tank size: 55 gallons (75+ is better)
Temperament: Peaceful
Adult fish size: 5 to 6 inches (13 to 15 cm)
Origin: South America
Temperature: 82 to 89°F (28 to 32°C)
pH: 6 to 6.5
Diet: Omnivore
Swim Level: Middle levels
Type: Centerpiece

It is possible to keep discus cichlids in a tank as small as 55 gallons, but this is a dedicated setup, not a casual one. Discus require soft, acidic water, warm temperatures (82 to 86°F / 28 to 30°C), and exceptional water quality maintained through frequent water changes. If you’ve always wanted to keep the king of the aquarium and have the commitment for it, a 55-gallon is a workable starting point.

6. Corydoras Catfish

Scientific name: Corydoras spp.
Care level: Easy
Minimum tank size: 30 gallons for most species
Temperament: Peaceful
Adult fish size: 2 to 3 inches (5 to 7.5 cm)
Origin: South America
Temperature: 74 to 80°F (23 to 27°C)
pH: 5.5 to 8
Diet: Omnivore
Swim Level: Bottom
Type: Bottom dweller

Corydoras catfish can be kept in tanks as small as 30 gallons, but a 55-gallon tank allows you to keep a larger school or even a few different species. These peaceful fish hang out on the bottom and search the substrate for leftover food scraps. There are many species available, including panda cories, Sterbai cories, and albino breeds. Keep a school of at least 5 of the same species and provide a sinking bottom feeder tablet.

7. Ram Cichlids

Scientific name: Mikrogeophagus ramirezi
Care level: Moderate to advanced
Minimum tank size: 20 gallons
Temperament: Peaceful
Adult fish size: 2.5 inches (6 cm)
Origin: South America
Temperature: 78 to 86°F (26 to 30°C)
pH: 5.5 to 7.5
Diet: Omnivore
Swim Level: Lower levels
Type: Centerpiece

The ram is a colorful dwarf cichlid from South America. These gorgeous fish are relatively shy and sensitive for a cichlid, but they make a great centerpiece in a soft-water 55-gallon planted tank. Ram cichlids prefer a sand substrate they can sift through in search of food. Set your heater in the low 80s°F (around 27 to 28°C) to recreate their natural habitat.

8. Neon Tetras

Scientific name: Paracheirodon innesi
Care level: Moderate
Minimum tank size: 10 gallons
Temperament: Peaceful
Adult fish size: 1.5 inches (4 cm)
Origin: South America
Temperature: 70 to 79°F (21 to 26°C)
pH: 6 to 7
Diet: Omnivore
Swim Level: Middle levels
Type: Schooling fish

Who says you can’t keep small fish in a big tank? The neon tetra is a classic community fish that thrives in a large aquarium filled with live plants and other small peaceful species. These fish look their best in a large school, and a 55-gallon is ideal. Aim for 20 or more neons for full effect in this size tank.

9. Small to Mid-Sized Plecos

Scientific name: Ancistrus spp., Hypancistrus spp., Panaques spp.
Care level: Easy to advanced (species dependent)
Minimum tank size: 20 gallons
Temperament: Peaceful
Adult fish size: 3 to 6 inches (7.5 to 15 cm)
Origin: South America
Temperature: Species dependent
pH: Slightly acidic to slightly basic
Diet: Herbivore
Swim Level: Bottom
Type: Bottom dweller

There are well over a hundred pleco species, some growing to more than a foot in length. In a 55-gallon, stick to species that max out under 6 inches (15 cm): bristlenose plecos, clown plecos, or rubber lip plecos. These peaceful bottom dwellers are safe with smaller fish and will help manage algae. Include plenty of rocks and driftwood for hiding spaces and food sources.

10. Geophagus

Scientific name: Geophagus spp., Satanoperca spp.
Care level: Moderate
Minimum tank size: 55 gallons for smaller species
Temperament: Generally peaceful
Adult fish size: 6+ inches (15+ cm)
Origin: South America
Temperature: Species dependent
pH: Species dependent
Diet: Omnivore
Swim Level: Lower levels
Type: Centerpiece

Geophagus are colorful South American cichlids that sift through the substrate in search of food. Keep them on a fine sandy substrate and choose smaller species that stay around 6 inches (15 cm) or under, such as Geophagus tapajos. These fish are not suited to a carefully aquascaped tank as they constantly rearrange the bottom.

11. Rainbowfish

Scientific name: Melanotaenia spp.
Care level: Easy to moderate
Minimum tank size: 30 gallons
Temperament: Peaceful
Adult fish size: 2 to 6 inches (5 to 15 cm)
Origin: Australia and Indonesia
Temperature: 74 to 80°F (23 to 27°C)
pH: 6.5 to 8
Diet: Omnivore
Swim Level: Middle levels
Type: Schooling fish

Rainbowfish are peaceful, active schooling fish that add color and movement to a 55-gallon aquarium. The 48-inch length of a standard 55-gallon suits their active swimming style particularly well. Popular species include the Boesmani rainbow and the smaller dwarf neon rainbow. Check out my guide to 15 popular rainbowfish types for species details.

12. Convict Cichlids

Scientific name: Amatitlania nigrofasciata
Care level: Easy
Minimum tank size: 30 gallons
Temperament: Aggressive
Adult fish size: 3.5 to 6 inches (9 to 15 cm)
Origin: Central America
Temperature: 74 to 84°F (23 to 29°C)
pH: 6.5 to 8
Diet: Omnivore
Swim Level: Lower levels
Type: Centerpiece

The convict cichlid is one of the easiest cichlids to keep and one of the most prolific breeders in the hobby. A breeding pair in a 55-gallon is entertaining and low maintenance, but be aware that these fish spawn so reliably that fry management becomes a real consideration. If you’re not prepared to deal with regular breeding, choose a different species.

13. Tiger Barbs

Scientific name: Puntigrus tetrazona
Care level: Easy
Minimum tank size: 30 gallons
Temperament: Semi-aggressive
Adult fish size: 3 inches (7.5 cm)
Origin: Southeast Asia
Temperature: 73 to 86°F (23 to 30°C)
pH: 6 to 8
Diet: Omnivore
Swim Level: Middle levels
Type: Schooling fish

Named for its orange body and four vertical black stripes, the tiger barb is an attractive schooling fish from Southeast Asia. These active barbs have a reputation for nipping, but they behave much better in large schools of 15 or more. Tiger barbs can coexist with fast-moving bottom-dwellers and other schooling fish. Avoid slow-moving tank mates or fish with long, flowing fins.

14. Rainbow Cichlid

Scientific name: Herotilapia multispinosa
Care level: Easy
Minimum tank size: 20 gallons
Temperament: Relatively peaceful
Adult fish size: 4 to 5 inches (10 to 13 cm)
Origin: Central America
Temperature: 72 to 82°F (22 to 28°C)
pH: 7 to 8
Diet: Omnivore
Swim Level: Lower levels
Type: Centerpiece

The rainbow cichlid is a beautiful Central American fish that is relatively peaceful for a cichlid. It has a golden color with a prominent black streak along each side that may break into blotches. A pair of rainbow cichlids is an excellent choice for a planted 55-gallon tank with suitable tank mates.

15. Denison Barb

Scientific name: Sahyadria denisonii
Care level: Easy
Minimum tank size: 55 gallons
Temperament: Peaceful
Adult fish size: 4 inches (10 cm)
Origin: India
Temperature: 59 to 77°F (15 to 25°C)
pH: 6.5 to 7.8
Diet: Omnivore
Swim Level: Middle levels
Type: Schooling fish

Also known as the roseline shark, denison barbs are one of the best-looking barbs in the hobby. These speedy schooling fish combine sleek lines and silvery scales with a bright red streak and yellow tail spots. A 55-gallon provides just enough swimming space for a small school (6+) of these peaceful fish. Denison barbs enjoy cooler water temperatures, so factor that in when selecting tank mates.

16. Electric Blue Acara

Scientific name: Andinoacara pulcher
Care level: Moderate
Minimum tank size: 40 gallons
Temperament: Semi-aggressive
Adult fish size: 6 to 7 inches (15 to 18 cm)
Origin: Trinidad and Venezuela
Temperature: 74 to 82°F (23 to 28°C)
pH: 6 to 7
Diet: Omnivore
Swim Level: Lower half
Type: Centerpiece

The electric blue acara is one of the most striking centerpiece fish available for a 55-gallon setup. The metallic blue coloration is exceptional under proper lighting. This cichlid is moderately sized, generally peaceful outside of breeding, and tolerates a reasonably wide range of water conditions. It pairs well with mid-level schooling fish that are too large to be seen as prey.

17. Jack Dempsey

The Jack Dempsey (Rocio octofasciata) is a bold, colorful cichlid that fits in a 55-gallon but will dominate it. Adults reach 7 to 8 inches (18 to 20 cm) and establish strong territorial claims. A single Jack Dempsey or a bonded pair is workable in a 55-gallon. Adding multiple males or mixing with other cichlids of similar aggression requires careful layout and monitoring. This is a personality fish. It will know you, recognize you at the glass, and reward the investment.

18. Oscar

Oscars (Astronotus ocellatus) grow to 12 to 14 inches (30 to 36 cm) and produce enormous waste loads. A 55-gallon is a starter tank for a juvenile oscar, not a permanent home. If you commit to an oscar, plan for a 75-gallon (284 L) minimum as an adult tank. The payoff is one of the most interactive, personality-driven fish in freshwater. They recognize their owners, beg for food, and rearrange their tank continuously. Just understand the commitment upfront.

19. Flowerhorn

Flowerhorns are hybrid cichlids with enormous humps (nuchal humps) on their heads and bold color patterns. They reach 12 inches (30 cm) and are exclusively a species-only fish. No tank mates. Like oscars, a 55-gallon works for juveniles but they need larger quarters as adults. They are one of the most visually dramatic fish you can keep in freshwater.

20. Betta Sorority

A betta sorority tank with multiple female bettas is an interesting option for a 55-gallon. It is not a beginner setup. Keep only females, a minimum group of five to spread out aggression, and have a backup plan if a fish becomes too aggressive. In the right hands this can be a stunning planted tank. In the wrong hands it creates a lot of injured fish.

21. Mollies

Scientific name: Poecilia spp.
Care level: Moderate
Minimum tank size: 20 gallons
Temperament: Generally peaceful
Adult fish size: 3 to 6 inches (7.5 to 15 cm) depending on species
Origin: North, Central, and South America
Temperature: 72 to 82°F (22 to 28°C)
pH: 7 to 8.5
Diet: Omnivore
Swim Level: Middle levels
Type: Schooling fish

Mollies are medium-sized livebearers ideal for a 55-gallon aquarium. Highly adaptable and available in many color varieties, they work well in a community tank or a dedicated livebearer tank with guppies and similar species. They prefer slightly hard water, which makes them a natural fit for livbearer-focused setups.

Avoid These 55-Gallon Stocking Mistakes

Using the inch-per-gallon rule. It is not a reliable stocking guide. It does not account for bioload, waste output, or swimming behavior. Use it as a rough starting point only, then research each species individually.
Putting an oscar or jack dempsey in with community fish. These are predators. They will eat or bully anything smaller. Species-only or carefully selected large tank mates only.
Mixing African cichlids with community fish. The pH and hardness requirements are incompatible. One group will always be in the wrong water.
Adding discus without understanding their temperature needs. 82 to 86°F (28 to 30°C) eliminates most community fish as tank mate options. This is a specialist setup from day one.
Choosing fish by appearance without checking adult size. The $3 fish that looks good in a 4-inch bag at the store may be 12 inches and producing more waste than your filter can handle in a year.

Choosing Your Stocking Approach: Community vs. Cichlid vs. Predator

Setup Type	Difficulty	Fish Count	Visual Impact	Maintenance	Best For
Community schooling	Beginner	25 to 50+	High (planted)	Weekly WC	First 55-gallon setup
Centerpiece species	Intermediate	2 to 15	Very High	Moderate to high	Showpiece builds
African cichlid colony	Intermediate	15 to 25	High (color)	Moderate	Active, colorful tanks
Single large predator	Intermediate	1 to 3	Moderate	High (bioload)	Personality fish keepers

Other Options

All the fish mentioned in this guide are excellent options for a 55-gallon setup, and there are hundreds more species that thrive in this versatile tank size. Looking for more inspiration? Check out these guides:

FAQ

What fish can you put in a 55-gallon fish tank?

55-gallon tanks are large enough for most popular freshwater aquarium fish sold in fish stores. The key is matching the fish to your water parameters and building a coherent stocking plan before you buy. Start with your water chemistry, decide on a tank concept (community, cichlid, predator), then select species that fit both.

What is the largest fish for a 55-gallon tank?

New World cichlids like oscars and jack dempseys are about the largest fish you can keep in a 55-gallon, though they prefer a larger tank when fully grown. A juvenile oscar works in a 55-gallon for the first year or so. An adult oscar at 12 to 14 inches (30 to 36 cm) needs a 75-gallon (284 L) minimum.

How do you stock a 55-gallon tank?

Start with your water parameters. Hard water suits livebearers and African cichlids. Soft water suits South American and West African species. Decide on your tank concept first, then choose species that fit it. Populate all three levels of the water column (bottom, mid-level, surface) for a balanced community setup.

How many fish can you have in a 55-gallon tank?

This depends entirely on species and bioload. A single adult oscar nearly maxes out a 55-gallon on its own. A school of chili rasboras at 0.7 inches (1.8 cm) each could number 40 or more in the same tank. Fish count is meaningless without species context. Focus on bioload and adult size, not number of fish.

What can I put in a 55-gallon tank besides fish?

Freshwater invertebrates like shrimp and snails, amphibians like axolotls and African dwarf frogs, and small freshwater turtles all work in a 55-gallon given the right setup and parameters.

Final Thoughts

A 55-gallon tank is genuinely one of the best investments in the freshwater hobby. It gives you enough volume to maintain stable water chemistry, enough footprint to suit schooling fish properly, and enough flexibility to try almost any freshwater concept you are interested in. The fish that does best in a 55-gallon is the fish you plan around from the beginning. Decide your concept, match your water parameters, and build the tank before you buy the fish. Every successful 55-gallon I’ve seen has followed that sequence. Every problem tank I’ve had to help troubleshoot over the years skipped it.

Where to Buy Quality Fish for a 55-Gallon Setup

These are the online suppliers I recommend for healthy, properly conditioned livestock:

Flip Aquatics – Quarantine-certified livestock, live arrival guarantee, and a wide selection of the species on this list. Use code ASDFLIPPROMO for a discount.
Dan’s Fish – Reliable source for community fish, cichlids, and specialty species. Good for stocking multiple species at once.

References

Seriously Fish – Species profiles and care data
FishBase – Taxonomy and scientific data
Practical Fishkeeping – Husbandry and care advice

March 2, 2024

Algae Eaters for Betta Tanks: My 7 Picks After Years of Betta Keeping

I’ve kept bettas for years, and algae is something almost every betta keeper deals with eventually. My personal go-to has always been nerite snails. They’re peaceful, do an excellent job on hard surfaces and glass, and won’t provoke even the most territorial betta. In a big enough tank, I’d pair them with an Otocinclus or two for extra coverage.

The thing most people miss: the moment you add any algae eater to a betta tank, you’re running a community setup. And community setup rules apply. Tank size matters more than people realize. A 5-gallon betta tank with a mystery snail is one thing. A 5-gallon with an Amano shrimp is a gamble. A 5-gallon with a Siamese algae eater is a disaster waiting to happen.

The list of algae eaters that actually work with bettas is short. That’s the honest answer. Most of the popular algae eaters are either too large, too active, too territorial about the same tank zones, or outright dangerous to pair with a betta. Here are the 7 that can actually work, with the full context on why each one does or doesn’t fit your setup.

EXPERT TAKE | MARK VALDERRAMA

After keeping bettas for years, my framework for evaluating any algae eater for a betta tank comes down to three questions: Does it share the same water column zone as the betta? Does it have features (long fins, bright colors, suckermouth behavior near the betta’s territory) that will trigger aggression? And is it big enough to be threatened by the betta but small enough to be harassed into stress? Nerite snails pass all three with zero concerns. Otocinclus pass if the tank is at least 20 gallons and well-established. Siamese algae eaters fail all three. That’s the framework. Apply it before you buy anything.

Key Takeaways

The safest algae eaters for bettas are nerite snails, mystery snails, and Otocinclus catfish
Most popular algae eaters are poor choices: Siamese algae eaters are too active and large, plecos are too territorial, and Chinese algae eaters become aggressive as adults
Algae eaters in a betta tank require at least a 20-gallon setup; anything smaller and you’re creating problems, not solving them
Supplement your algae eaters with targeted food; they will not survive on tank algae alone
Live plants are the most sustainable long-term algae management tool; algae eaters are a complement, not a standalone solution

What Is Algae and Why Does It Grow?

Algae are photosynthetic organisms that thrive when light and nutrients align in the right conditions. In a betta tank, that usually means: too much light duration, excess nutrients from overfeeding, or not enough plant competition to absorb available nutrients.

Algae blooms are normal in new tanks cycling for the first time. Some algae in a mature aquarium is also completely normal and not a problem that needs solving. The goal isn’t zero algae. The goal is control.

There are many types of aquarium algae, and they don’t all respond the same way to algae eaters. Green spot algae (the hard stuff on glass) is great territory for nerite snails. Soft green hair algae is Otocinclus food. Black beard algae is barely touched by any fish. A UV sterilizer handles green water (suspended algae). No single algae eater handles everything, and some algae types require non-biological solutions entirely.

The Betta Compatibility Challenge

Bettas were selectively bred for fighting. That history still shows up in a lot of individuals, particularly males. Betta aggression toward tankmates is individual and situational. Some bettas are remarkably calm. Others will attack anything that enters their line of sight.

The compatibility challenge with algae eaters specifically:

Many algae eaters are bottom or glass dwellers. Bettas hang in the middle to upper column. Zone separation helps.
Long-finned, flowing, or brightly colored algae eaters trigger fin nipping from the betta or aggression in the other direction. Avoid anything that looks like it could be mistaken for a betta rival.
Suckermouth catfish that attach to surfaces near the betta’s resting spots create territory conflicts that escalate fast.
Small, stressed algae eaters become targets for harassment. If the algae eater is small enough to look like prey, assume it’s at risk.

The biggest mistake I see: people add algae eaters to a 5 or 10-gallon betta tank without accepting that they’re now running a community setup. The moment you add another inhabitant, everything about tank size, filtration, territory, and stress tolerance becomes critical. My recommendation: if you want algae eaters with your betta, aim for at least a 20-gallon (76 L) tank. And always have a backup plan.

TIER BREAKDOWN

Safest (minimal betta conflict risk): Nerite Snails, Mystery Snails
Good with the right setup (20+ gallon, established tank): Otocinclus, Amano Shrimp, Ghost Shrimp
Situational (individual betta dependent): Corydoras, Malaysian Trumpet Snails
Avoid entirely with bettas: Siamese Algae Eater, Chinese Algae Eater, Bristlenose Pleco, Common Pleco, any large suckermouth catfish

Algae Eater for Betta Tank: 7 Top Picks

These are the options that can realistically work. The list is deliberately short because most algae eaters don’t belong in a betta setup.

1. Otocinclus Catfish

Scientific Name: Otocinclus sp.
Care Level: Moderate
Adult Size: 1.5–2 inches (4–5 cm)
Min Tank Size: 20 gallons (76 L) with betta
Temperature: 72–82°F (22–28°C)
pH: 6.0–7.5
Algae Specialty: Soft green algae, diatoms, biofilm on glass and plant leaves

Otocinclus are small, peaceful, and occupy the lower water column without encroaching on betta territory. They’re excellent soft algae cleaners and leave the betta completely alone. The challenges: they need an established tank with existing algae growth to feed on, and they need supplemental food (blanched zucchini or algae wafers) because they will starve in a clean tank. They also do best in groups of 4 or more, which requires the tank space to support them.

In a 20-gallon or larger with a non-aggressive betta, a small group of Otocinclus is one of the better combinations available.

2. Nerite Snails

Scientific Name: Neritina sp.
Care Level: Easy
Adult Size: 0.5–1 inch (1.3–2.5 cm)
Min Tank Size: 5 gallons (19 L)
Temperature: 72–78°F (22–26°C)
pH: 7.0–8.0
Algae Specialty: Green spot algae, diatoms, hard surface algae on glass and decor

The safest algae eater for a betta tank, period. Nerites stay on glass and hard surfaces, have no features that trigger betta aggression, and are practically indestructible from a care standpoint. They won’t reproduce in freshwater (eggs require brackish conditions to hatch), so no snail population explosion. The only downsides: they lay white eggs on surfaces that are cosmetically annoying to some keepers, and they don’t eat every algae type.

If someone asks me for one algae eater recommendation for a betta tank, this is it every time.

3. Mystery Snails

Scientific Name: Pomacea bridgesii
Care Level: Easy
Adult Size: 1.5–2 inches (4–5 cm)
Min Tank Size: 5 gallons (19 L)
Temperature: 68–82°F (20–28°C)
pH: 7.0–8.0
Algae Specialty: Soft algae, biofilm, decaying plant matter

Mystery snails are larger than nerites and more visible, which means some bettas will investigate them aggressively. Most bettas lose interest once they realize the snail is hard-shelled and not worth the effort. Watch for the first few days after introduction: if your betta is actively harassing the snail and preventing it from feeding, remove it. Otherwise, mystery snails are peaceful, attractive, and useful tank cleaners beyond just algae.

4. Amano Shrimp

Scientific Name: Caridina multidentata
Care Level: Easy–Moderate
Adult Size: 1.5–2 inches (4–5 cm)
Min Tank Size: 20 gallons (76 L) with betta
Temperature: 70–80°F (21–27°C)
pH: 6.5–7.5
Algae Specialty: Hair algae, soft algae, organic debris

Amano shrimp are the best shrimp option for betta tanks because their size makes them less vulnerable than smaller cherry shrimp. They’re vigorous algae eaters, particularly for hair algae, and they work quickly. The risk: individual bettas vary in how they react to shrimp. Some ignore them completely. Others hunt them relentlessly. Plants and hiding spots reduce the risk significantly. In a well-planted 20-gallon with a calm betta, Amano shrimp work well.

5. Ghost Shrimp

Scientific Name: Palaemonetes sp.
Care Level: Easy
Adult Size: 1–1.5 inches (2.5–4 cm)
Min Tank Size: 10 gallons (38 L) with betta
Temperature: 65–82°F (18–28°C)
pH: 7.0–8.0
Algae Specialty: Soft algae, biofilm, food particles

Ghost shrimp are transparent and small, which makes them less triggering to bettas visually but also more vulnerable if the betta decides to hunt. Their near-invisibility is a partial protection. They’re not the most effective algae eaters on this list, but they’re inexpensive enough that if your betta eats a few, it’s not a major loss. Good for tanks where you want some biological cleanup activity without significant risk.

6. Malaysian Trumpet Snails

Scientific Name: Melanoides tuberculata
Care Level: Easy
Adult Size: 0.5–1 inch (1.3–2.5 cm)
Min Tank Size: 5 gallons (19 L)
Temperature: 70–80°F (21–27°C)
pH: 6.5–8.0
Algae Specialty: Substrate biofilm, detritus, soft surface algae

Malaysian trumpet snails live primarily in the substrate, which means bettas barely notice them. They burrow, aerate the substrate, and consume detritus and substrate biofilm. The downside: they breed prolifically in response to available food. Population control requires reducing feeding and manual removal. They’re not primarily an algae eater, but their substrate cleaning function is genuinely useful and the betta compatibility is excellent.

7. Corydoras Catfish

Scientific Name: Corydoras sp.
Care Level: Easy
Adult Size: 1–2.5 inches (2.5–6.4 cm) depending on species
Min Tank Size: 20 gallons (76 L) with betta
Temperature: 72–82°F (22–28°C)
pH: 6.0–7.5
Algae Specialty: Soft substrate algae and biofilm; more of a scavenger than a dedicated algae eater

Corydoras are peaceful bottom dwellers that stay out of the betta’s mid-water territory. They’re not primarily algae eaters: they’re omnivorous scavengers that eat leftover food, detritus, and soft substrate algae as part of their diet. They won’t solve an algae problem, but they contribute to overall tank cleanliness and get along with most bettas. They need groups of 4 or more, which means they’re only appropriate in 20+ gallon betta setups.

Species	Difficulty	Max Size	Min Tank	Notes
Otocinclus	Moderate	2 in (5 cm)	20 gal	Best algae cleaner; needs established tank and supplement feeding
Nerite Snail	Easy	1 in (2.5 cm)	5 gal	Safest overall pick; no reproduction in freshwater
Mystery Snail	Easy	2 in (5 cm)	5 gal	Watch for betta harassment; usually fine after initial curiosity
Amano Shrimp	Easy–Moderate	2 in (5 cm)	20 gal	Best shrimp option; betta temperament dependent
Ghost Shrimp	Easy	1.5 in (4 cm)	10 gal	Near-invisible; lower risk but also less effective
Malaysian Trumpet Snail	Easy	1 in (2.5 cm)	5 gal	Substrate cleaner; control population by managing food
Corydoras	Easy	2.5 in (6.4 cm)	20 gal	Scavenger more than algae eater; peaceful, needs group of 4+

MARK’S PICK

Nerite snails are my top recommendation for any betta tank. They work on the algae that matters most (green spot on glass, diatom film), they’re impossible for a betta to bother effectively, and they don’t reproduce in freshwater. If your tank is at least 20 gallons and has been running for a few months, add 4–6 Otocinclus alongside 2–3 nerites and you’ll have the best coverage possible without any meaningful betta conflict risk. That combination handles the two most common betta tank algae types without drama.

Algae Eaters That Don’t Belong in a Betta Tank

This is important. The hobby markets a lot of algae eaters that sound plausible for betta tanks but create serious problems in practice.

Siamese Algae Eater

Too large (up to 6 inches / 15 cm), too active, and they share the mid-water column with bettas. Their movement triggers territorial responses, and they get harassed or become harassers. Not a betta tank fish.

Chinese Algae Eater

Juvenile Chinese algae eaters are peaceful algae eaters. Adults become territorial, aggressive, and will latch onto the sides of flat-bodied fish. They’ve been documented attacking and damaging angelfish and goldfish the same way. A betta is not a safe companion for an adult Chinese algae eater.

Common Pleco

Grows to 24 inches (61 cm). The minimum tank size for an adult common pleco alone is 100 gallons (379 L). Anyone selling these as betta tank algae eaters is doing the buyer a serious disservice.

Bristlenose Pleco

A more reasonable size (up to 5 inches / 13 cm), but they’re territorial about surface areas and hiding spots. In a small betta tank they create territory conflicts with the betta’s preferred resting spots. In a 30-gallon or larger with plenty of caves and driftwood they can work, but they’re not the low-conflict option most people assume.

AVOID IF

Don’t add any algae eater to a betta tank if: your tank is under 10 gallons (and under 20 gallons for anything other than snails); your betta has previously attacked snails or tankmates; you can’t provide hiding spots and visual breaks; or you’re not prepared to remove the algae eater if aggression happens. Also avoid algae eaters entirely if your tank is under 3 months old: Otocinclus in particular need established biofilm to survive. A newly cycled tank will starve them regardless of betta compatibility.

Live Plants: The Best Long-Term Algae Control

Live plants outcompete algae for the same nutrients. A well-planted betta tank with appropriate lighting rarely develops serious algae problems because the plants consume what algae would otherwise use to grow.

Easy betta-compatible plants: java fern, anubias, hornwort, water sprite, and floating plants like frogbit or dwarf water lettuce. Floating plants are particularly effective because they reduce light penetration, which cuts off one of the two things algae need most.

Algae eaters are a complement to live plants, not a replacement for them. The combination of plants, nerites, and Otocinclus in a well-maintained 20-gallon is practically algae-proof. A 10-gallon betta tank with no plants relying solely on algae eaters is fighting an uphill battle.

Where to Buy

Nerite snails and mystery snails are available at most fish stores. Otocinclus are common but their health at point of sale varies significantly: look for active fish that are clearly grazing, not fish huddled at the surface or bottom. Emaciated Otocinclus rarely recover.

For quality guaranteed livestock, Flip Aquatics carries a reliable selection of algae eaters, snails, and shrimp. Dan’s Fish is another solid online source for Otocinclus and quality snail stock.

FAQs

Will a betta fish eat my algae eater?

It depends on the species and the individual betta. Snails are safe from being eaten because of their shells. Shrimp are at real risk, especially smaller species like cherry shrimp. Otocinclus are rarely eaten but can be harassed. The safest algae eaters from a predation standpoint are snails: nerites and mystery snails specifically.

Can I put a pleco in my betta tank?

Common plecos are absolutely not appropriate for betta tanks. Bristlenose plecos can work in tanks of 30 gallons or larger with enough territory and decor. But they’re not the passive, conflict-free option they’re often marketed as. If you’re looking for low-drama algae control, start with nerite snails.

How many nerite snails should I get for a betta tank?

One nerite snail per 5 gallons (19 L) is a reasonable starting guideline. In a 10-gallon betta tank, 2 nerites handle the glass and surfaces effectively. In a 20-gallon, 3–4 nerites alongside an Otocinclus group gives comprehensive coverage.

Do algae eaters help with all types of algae?

No. Green spot algae on glass and diatom film: nerites and Otocinclus handle these well. Hair algae: Amano shrimp are the better choice. Black beard algae: almost nothing eats it reliably. Green water (suspended algae): no fish handles this; use a UV sterilizer. Match the algae eater to the algae type you’re dealing with.

What if my betta attacks the algae eater I added?

Remove the algae eater immediately if persistent harassment is occurring. A stressed Otocinclus or shrimp will die within days. Some bettas simply will not tolerate any tankmates regardless of species. That’s the betta’s personality, not a failure of the setup, and there’s no forcing a solution. Snails are the only exception where the betta’s aggression generally can’t cause actual harm.

Closing Thoughts

The list of algae eaters that genuinely work with bettas is short because betta compatibility is a real constraint, not a minor consideration. Nerite snails are the right starting point for almost everyone. If your tank is big enough and your betta’s temperament allows it, Otocinclus are the upgrade.

Don’t overthink the algae problem. In most betta tanks, two or three nerite snails, consistent feeding discipline (overfeeding drives most algae blooms), and a couple of easy live plants solve the issue completely. The fancy algae eaters are for bigger setups where betta aggression has less impact.

For quality snails, Otocinclus, and shrimp for your betta tank, check out Flip Aquatics and Dan’s Fish.

February 26, 2024

Vegetables for Fish: What I Feed My Tanks After 25 Years (And What to Avoid)
I’ve been feeding vegetables to my fish for years. Nori sheets for saltwater tanks, and cucumbers and romaine lettuce for freshwater setups. It’s one of the most underrated things you can do for herbivorous and omnivorous fish, and once they find it, they go for it every time. One critical step most people skip: blanching. Leave it out and you risk fouling your water with pesticide residue and disintegrating plant matter. This guide covers what actually works, what doesn’t, and how to prepare it correctly.
Key Takeaways
- Aquarium fish can be given an assortment of raw and frozen vegetables!
- Veggies are a great way to keep fish healthy by introducing vitamins and minerals that aren’t offered in typical fish food.
- Vegetables can be easily blanched and frozen for easy storage and long-term use.
- Some fish don’t like vegetables or have never been offered them, so algae wafers are a good alternative instead!
Vegetables For Fish – Which Are The Best Ones?

The best vegetable to feed fish (video from our official YouTube Video) is one that will withstand being submerged, at least for an hour or two. This vegetable should not start to disintegrate once a hungry fish starts to get to it. Luckily, a variety of vegetable options can be blanched and eaten by fish.

A good list of rotating veggies might look like:
- Broccoli
- Cucumber
- Zucchini
- Yellow squash
- Spinach
- Romaine lettuce
- Carrot
- Peas
- Nori (great for saltwater fish)
Not all fish will like all vegetables, so it might take some time to figure out which ones to include in your feeding rotation. Most hobbyists like to weigh small pieces down with a rubber band around a rock or a suction clip that attaches to the side of the glass.

🏆 My personal picks: For freshwater tanks, cucumbers are my go-to. fish love them, they hold up well submerged, and they’re easy to prep. For saltwater, Nori (dried seaweed sheets) is the clear winner. tangs and rabbitfish will go absolutely crazy for it on a clip. I’ve also had great results with romaine lettuce in freshwater setups.

Does Your Aquatic Pal Need Them?

Before we even start to discuss how to prepare fresh vegetables for your fish, you need to know if these foods would be similar to something that they would naturally come across in the wild. A carnivorous fish will probably not eat a cucumber, no matter how appealing it might look!

Most likely, you won’t be able to tell whether a fish is a carnivore, herbivore, or omnivore just by looking at it. There might be some signs, like sharp teeth or a sucker mouth, but even then, you can’t be fully sure. The best way to find out the natural diet of your fish species is by doing research about their natural habitat and hearing experiences from other hobbyists or your local aquarium store.

Once you’ve established the natural diet of your fish, you can begin catering to it. If it turns out that you have a herbivore fish, then you might start to supplement blanched vegetables into their diet.

Benefits of Veggies

There are many benefits to giving vegetables to fish. The main benefit is keeping fish healthy by supplementing vitamins and minerals that aren’t supplied through typical fish food¹.

The other main benefit is enrichment. By now, you’ve probably noticed that your fish waits to be fed at the top of the aquarium anytime you walk by. Feeding time is what they look forward to! Adding veggies is a great way to make feeding time even more exciting and unpredictable while also adding variety and balance to your fish’s diet.

What Are Blanched Vegetables?

Simply put, blanching means submerging vegetables or fruits into boiling water for a short period, quickly removing them, and then placing them into a bowl of water with ice. This process only takes a couple of minutes but helps preserve the quality of the vegetable or fruit.

There are a few ways blanching achieves preservation. First, it inactivates enzymes that would otherwise begin to affect color, taste, and nutritional value over time. Similarly, blanching affects bacteria which would also cause the product to degrade faster.

Blanching is especially recommended when using vegetables as fish food due to insecticides and other residues. Unfortunately, many unknowns are used to treat food for consumption, so boiling them first reduces the chances of those chemicals entering the aquarium.

⚠️ The biggest mistake I see: People skip blanching entirely. Raw, unblanched vegetables can foul your water fast as they break down, and you’re putting pesticide residue directly into your tank. Blanching takes about two minutes and makes a real difference. don’t skip it.

All in all, blanching fresh fruits and vegetables helps preserve them for longer and allows for easy freezing and storage. In the aquarium setting, most hobbyists only offer vegetables as fruits can be messy.

Can You Serve Them Raw?

Yes! Tropical fish can be fed raw vegetables. Blanching is recommended for hobbyists who want to keep vegetables on hand for future use. There are a couple of things that need to be considered, though.

As mentioned before, veggies are often treated with chemicals and other preservatives. These should be thoroughly washed off before being added to the tank. It is also likely that these pieces of raw vegetables will end up floating on the surface of the water, so it might take some extra effort to weigh them down.

How To Blanch Them

Almost any vegetable can be blanched, but not every blanched vegetable is good for the aquarium. Instead, certain hard vegetables, like broccoli, cucumber, zucchini, and peas, are some of the favorite feeding options for herbivores. This is because other vegetable matter can easily break down and start to affect water quality.

Vegetables with strong aromas, like brussels sprouts and onions, should be avoided as they can start to affect water conditions as well.

Buying Them

This might seem obvious, but you need to purchase your vegetables at the grocery store. Your local fish store will not have fresh vegetables! Now the question comes down to picking the right veggies for your fish.

Should you buy organic?

You definitely want to pick the best vegetables possible to feed your fish, and you should be mindful of what you’re putting in the aquarium. However, there is likely little difference between buying organic and using regular produce. The blanching process should hopefully remove any chemicals or additives in either option.

If you want to feed raw cucumber or another vegetable fresh from the rack, then it may be the better choice to buy organic.

Preparation

Depending on what type of vegetables you get for your fish, you might need to do some prep work. Think about how much food you want to give to your fish, for how long, and if you could use the leftovers for your own consumption!

Some vegetables, like zucchini, cucumber, and broccoli, will need to be cut up into manageable pieces. The goal should be to slice to expose as much of the soft, inside flesh as possible as fish will likely eat these sections first. For something like zucchini, slice each piece to be about 0.5 inches. Most other vegetables, like spinach and lettuce, can be split apart and fed more easily.

Now, you will want to consider how long you want to serve your fish this food. Fish eat as much as is available, so it’s not recommended to give it all at once. But you don’t want to be feeding the same thing for a month either! Prepare enough food for several feedings. Save some for blanching and save some for the dinner table.

Blanching Steps

Now it’s finally time to blanch the veggies. This process is straightforward and easy and almost impossible to mess up.
1. Bring a pot of water to a rolling boil. The boiling water will activate those processes we talked about earlier!
2. Fill a separate bowl with water and ice.
3. Add the sliced vegetables to the boiling water.
4. Allow them to boil for 1-3 minutes depending on the size of the slices.
5. Remove the vegetables when they’re crispy. A crunchy vegetable needs more time and a mushy vegetable has gone too long.
6. Add the veggies to the ice bath. Let them sit in the cold water for a minute or two.
7. If you’re planning on freezing the vegetables, then wait until they’re completely cooled and dried. Then, store them in a plastic bag in the freezer.
Feeding Your Fish

When you’re ready to feed your fish, make sure to fully thaw the frozen vegetable matter. You may need to weigh it down with a rock or clip so that it doesn’t float.

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Allow your fish to eat. It might take some time for them to find and understand that the vegetable matter is food. Snails are also naturally slow!

After a couple of hours, remove what remains of the veggies. If your fish and snails liked what they were given, you might just find vegetable skin left over.

How Often To Feed Vegetables?

How often you feed your fish fresh or frozen vegetables will depend on how many fish are present and their feeding habits.

If you have a larger tank with lots of tropical fish, shrimp, and snails, then you will need more food to make sure that everyone is getting fed. Always make sure to keep an eye on uneaten food and remove any pieces that could potentially get stuck in the back of the tank.

In general, fresh and frozen vegetables can be given one to two times a week to create a well-balanced diet.

Alternatives

While most aquarium fish enjoy a veggie snack every now and then, some fish simply don’t like vegetables, even if they’re herbivores.

It makes sense why a carnivorous fish might not eat veggies, but why wouldn’t a herbivore?

It is possible that your fish was never introduced to any foods other than flake or pellet foods. They might not know how to eat veggies! In cases like this, you can continue to offer your fish fresh vegetables until they take a nibble, or you could settle with a high-quality algae wafer or pellet.

For saltwater fish, consider a product like Julian Sprung’s Sea-Veggies

Great For Algae Eaters

Sea Veggies Seaweed Green

Sea veggies is an amazing product for Tangs, Rabbitfish, and Marine Angelfish. Fish go crazy for it. Clean and easy to feed!

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FAQs

What vegetables can I feed my fish?

Tropical fish love most vegetables! But every fish will have its own appetite. The best veggies to feed fish include lettuce, peas, zucchini, and cucumber. These can be given raw or frozen as long as they are prepared and thawed before serving.

Can I feed my fish fruits?

While fruits can be blanched and stored for serving later, it’s not recommended to give fruits to fish. This is because fruit is high in sugar, which can easily start to affect aquarium water. Because of this, it’s generally recommended to only give fish vegetables.

How do I make prepared fish foods?

Feeding vegetables to fish is quick and easy! Depending on the type of veggie you’re giving, you may need to cut it up into small pieces. These pieces can then be washed and added directly to the tank or blanched and saved for later.

Why didn’t my fish eat vegetables?

Every fish is different and yours might not enjoy vegetables! Instead, you can supplement those vitamins and minerals with algae wafers or pellets.

How do I make prepared fish foods?

Feeding vegetables to fish is quick and easy! Depending on the type of veggie you’re giving, you may need to cut it up into small pieces. These pieces can then be washed and added directly to the tank or blanched and saved for later.

Why didn’t my fish eat vegetables?

Every fish is different and yours might not enjoy vegetables! Instead, you can supplement those vitamins and minerals with algae wafers or pellets.

Can saltwater fish eat vegetables?

Yes! Saltwater fish can also be given vegetables even though they’re unlikely to experience plant matter in their natural habitats. Because of this, saltwater fish are more likely to ignore vegetable offerings, but some might take a nibble.

Instead, saltwater fish can be offered different types of macroalgae and seaweed sheets. The most common type of veggie before Nori was popular was romaine lettuce.

Conclusion

Most fish love a selection of fresh veggies in addition to their staple fish flakes or pellet, though some fish don’t! These vegetables can be served raw or blanched and frozen for later use. Some options include lettuce, peas, carrots, and broccoli, but an algae wafer will substitute for more picky fish.

Keep in mind that feeding fresh veggies can be messy and not all fish will enjoy the offer! Uneaten food should be removed if left untouched after a couple of hours.

🐟 Want to learn more? This article is part of our complete Aquarium Care Guide. your ultimate resource for water chemistry, maintenance, feeding, disease prevention, and everything you need for a healthy tank.
February 24, 2024
Zebra Danio Tank Mates: My 21 Picks After Years in the Hobby
I’ve kept zebra danios and they’re about as bulletproof as freshwater fish get. hardy, active, and incredibly easy to care for. But that high energy level is exactly what trips people up when selecting tank mates. These fish need space to zoom around, and I wouldn’t attempt a community setup in anything smaller than a 20-gallon tank. Add in their preference for cooler water and you have two things most people don’t think about until it’s too late. In this guide I’ll walk you through my 21 top picks. and the combinations to avoid.
Key Takeaways
- The zebra danio is a hardy, active fish that can be kept with a variety of species.
- These fish do best in a coldwater setup but can be acclimated to warmer conditions.
- Some of the best zebra danio tank mates are tetras, rasboras, and corydoras.
- Tank mate species to avoid include bettas, aggressive cichlids, and fish with large mouths.
Intro

Before we can talk about tank mates, we need to understand zebra danio care.

Zebra danios, scientifically known as Danio rerio, are highly adaptable freshwater fish native to many regions throughout Asia. These fish can be found in cold to hot fast-moving or stagnant conditions across India, Pakistan, Nepal, Bangladesh, and Bhutan; they have been introduced to many other regions of the world, including South America and North America. They usually live alongside vegetation but don’t rely on it for survival¹.

These freshwater fish grow to be about 1 to 2 inches on average and are named after the alternating silver and bluish-black horizontal stripes along the sides of their body. They have a torpedo-shaped body that helps propel them through the water.

Zebra danios are a very important species for science. They are considered a scientific model organism, which allows for many avenues of biological study. In fact, a zebra danio has even been sent to outer space! Interestingly, there is also evidence that zebra danios have memory, which means that they may experience some level of consciousness.

Tank Size

It is no wonder why the zebra danio is a favorite addition to the aquarium setting due to its high adaptability. These are easy-to-keep fish that bring a lot of movement to the upper portions of the aquarium.

Zebra danios are a schooling fish, which means that you need to allow space for at least 6 or more individuals. In general, a school of zebra danios can comfortably fit in a 10 gallon aquarium with minimal other fish. However, a 20 gallon long aquarium will allow for a bigger school as well as other tank mates.

Aqueon 20 Gallon Tank

A classic 20 gallon aquarium in its 30 inch long variant. A very popular aquarium.

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Water Temperature

One of the most important aspects to keep in mind when keeping zebra danios is their need for cooler water conditions. While these peaceful fish have been documented across a 50 degree range, they seem to do best when the water temperature is kept stable between 65-82° F.

⚠️ The biggest tank mate mistake I see: Fishkeepers pair zebra danios with tropical fish that need warmer water, or slow-moving species that can’t handle their energy. Danios are fast and constantly on the move. timid or slow fish will be stressed by them. Always match both temperature range and activity level when choosing tank mates, and remember: nothing smaller than a 20-gallon if you want this to work.

The Top Zebra Danio Tank Mates

Now that we have some understanding of where zebra danios come from and how they live in both their natural habitat and in the aquarium, we can start to consider some tank mate options.

The best zebra danio tank mates will be able to live with an active fish in colder-than-normal water temperatures.

1. Harlequin Rasboras

Harlequin Rasbora

A peaceful schooling fish. An ideal community fish. A great beginner fish

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- Scientific Name: Trigonostigma heteromorpha
- Tank Size: 10 gallons
- Adult Size: 1-2 inches
- Water Temperature: 71-80° F
- Temperament: Peaceful
Harlequin rasboras are small, colorful orange and black fish that resemble tetras. They are schooling fish that need to be kept in groups of at least 6 or more. Together, they are active swimmers that will stay in the middle portions of the aquarium.

With more active fish, like the zebra danio, harlequin rasboras may school tighter together and be less active. However, with a larger tank, the two species will complement each other in terms of activity and color.

2. Cory Catfish
- Scientific Name: Corydoras spp.
- Tank Size: 10 gallons
- Adult Size: 1-5 inches
- Water Temperature: 70-80° F
- Temperament: Peaceful
There are many different species of corydoras available in the aquarium hobby, coming in a variety of sizes. These are bottom-dwelling fish that like to school far away from zebra danios at the top of the water column. This distance, in addition to cories preferring slightly cooler-than-normal water conditions, makes them a good pairing for zebra danios.

🏆 My top pick for a zebra danio tank mate: Cory catfish are my go-to recommendation. they occupy the bottom while danios work the top, so there’s zero competition for space. The shared preference for slightly cooler water makes the parameter match easy too. I’ve seen this pairing work beautifully, and it’s the first thing I suggest to anyone setting up a danio community tank.

Some of the most popular Corydoras options include the bronze cory (Corydoras aeneus), pygmy cory (Corydoras pygmaeus), panda cory (Corydoras panda), and Sterba’s cory (Corydoras sterbai).

3. Mollies
- Scientific Name: Poecilia spp.
- Tank Size: 15 gallons
- Adult Size: 3-5 inches
- Water Temperature: 72-82° F
- Temperament: Peaceful to semi-aggressive
Mollies are one of the most popular freshwater fish. Mollies are large fish that come in almost every color, with many different varieties available.

They not true schooling fish, but they do enjoy the company of at least two to three others. This, in addition to their size, means that they are good feature fish for tanks over 10 gallons.

It is important to note that while mollies are often seen as community tank fish, they are capable of showing aggression to other fish and each other, especially if there are multiple males in the tank during breeding times. They also prefer the upper portions of the water column. Because of this, it’s important to watch how your mollies and zebra danios interact.

4. Swordtails
- Scientific Name: Xiphophorus hellerii
- Tank Size: 20 gallons
- Adult Size: 3-6
- Water Temperature: 64-82 °F
- Temperament: Peaceful to semi-aggressive
Swordtails are very similar to mollies in terms of color, activity, and behavior. These fish come in all different color variations and are easily recognized by their extended tail fin. They can also be kept in cooler water temperatures.

These fish are not a schooling species but exhibit shoaling behaviors in small groups with one male and several females. Swordtails are relatively active fish that like to stay in the upper portions of the aquarium. They can become aggressive towards other fish and their own if more than one male is present.

While swordtails are generally peaceful towards zebra danios, hobbyists should look out for possible fin-nipping and competition during feeding times.

5. Neon Tetras

Neon Tetra

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One of the most popular freshwater community schooling fish available in the aquarium trade. Great neon blue colors!

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- Scientific Name: Paracheirodon innesi
- Tank Size: 10 gallons
- Adult Size: 1.0-1.5 inches
- Water Temperature: 72-82° F
- Temperament: Peaceful, shy
Neon tetras get along with most freshwater fish, and zebra danios are no exception. These small red and blue fish can be timid, especially when kept in smaller groups. Luckily, they only grow to be about an inch big, which allows for more room for keeping a bigger school. This is necessary as zebra danios can potentially stress them out.

The good news is that neon tetras and zebra danios generally live in two different areas of the tank. Neon tetras usually stay in the middle and lower portions of the aquarium, away from the hustle and bustle of danios. Still, some extra decorations and hiding spots might encourage your tetras to be more present.

6. Rummy Nose Tetras

Rummy Nose Tetra

An easy to care for Tetra fish that loves to school. Very peaceful fish that are great for beginners

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- Scientific Name: Hemigrammus bleheri
- Tank Size: 10 gallons
- Adult Size: 1-2 inches
- Water Temperature: 75-85° F
- Temperament: Peaceful, active
Rummy nose tetras have a similar appearance and behavior to the zebra danio, but they’re a little more challenging to keep. These peaceful fish are identifiable by their bright red faces and can be seen swimming in schools in the upper portions of the water column.

While rummy nose tetras make a good option for a zebra danio community tank, they are much more sensitive to incorrect and changing water conditions than other fish species. These fish do especially well in bigger groups in a heavily planted tank.

7. Apistogrammas

Apistogramma cacatuoides” class=”wp-image-1059938″/>
- Scientific Name: Apistogramma spp.
- Tank Size: 20 gallons
- Adult Size: 2-3 inches
- Water Temperature: 72-86° F
- Temperament: Semi-aggressive
If you want another fish species to be the star of your aquarium instead of your zebra danio school, then an Apistogramma cichlid might make the ideal tank mate. These dwarf fish are from South America and are one of the more peaceful species of cichlid available. They have a moderate temperament but will readily tolerate other small, peaceful fish.

The trick to choosing good Apistogramma tank mates is selecting fish that can’t be mistaken for another cichlid and that stay out of their way during breeding periods. This makes the zebra danio a good option.

8. Chili Rasboras

Chili Rasboras

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A great nano schooling fish. Males display brighter colors. Best in groups of 6 or more

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- Scientific Name: Boraras brigittae
- Tank Size: 10 gallons
- Adult Size: <1 inch
- Water Temperature: 70-82 °F
- Temperament: Peaceful, shy
If you’re looking for something even smaller than the zebra danio, chili rasboras are about as tiny as you can get. There are a few considerations that will need to be made before making these two tank mates, though.

Chili rasboras are extremely small fish that grow to be less than an inch big. They love to school at the top of the water column but will scatter if threatened. Unfortunately, this can sometimes become problematic if you have an especially active or bold zebra danio.

If you find that your chili rasboras are overwhelmed by your zebra danio school, then you may need to increase the size of your rasbora school, add more plants, or reconsider rehoming one of the species.

9. Ember Tetras

Ember Tetra

A small red tetra that grows up to 1.25 inches. A very peaceful schooling fish

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- Scientific Name: Hyphessobrycon amandae
- Tank Size: 10 gallons
- Adult Size: 1 inch
- Water Temperature: 72-80 °F
- Temperament: Peaceful
While not exactly the same, ember tetras are a good (and cheaper) alternative to chili rasboras. These two fish share some of the same orangey-red colors and ember tetras only grow to be a little bigger.

Unlike chili rasboras, ember tetras are hardy fish that prefer the middle and lower portions of the water column. They take comfort in a school of 6 or more and can withstand the activity of a zebra danio school.

For most hobbyists, ember tetras are a better addition to the zebra danio community tank than chili rasboras.

10. White Cloud Minnows

White Cloud Mountain Minnow

A very peaceful fish that does well in coldwater fish. Other minnow varieties are also available

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- Scientific Name: Tanichthys albonubes
- Tank Size: 10 gallons
- Adult Size: 1-2 inches
- Water Temperature: 57-72°F
- Temperament: Peaceful, active
White cloud minnows are one of the best zebra danio community tank mate options, period! This is because their tank size, adult size, water temperature, and temperament all align.

White cloud minnows are not tropical fish and are instead, minnows. This means that they are incredibly hardy fish that can withstand a wide range of water temperatures and parameters. They are also active schooling fish that enjoy their own company and that of other fish species.

11. Boesemani Rainbowfish
- Scientific Name: Melanotaenia boesemani
- Tank Size: 40 gallons
- Adult Size: 4-5 inches
- Water Temperature: 72. 77° F
- Temperament: Peaceful, active
The Boesemani rainbowfish and the zebra danio is an odd pairing, but it’s doable! Both of these species are very active and a larger tank will be needed to comfortably keep both. While zebra danios will mostly stay towards the top of the tank, plenty of room should also be allowed for an active school of rainbowfish in the middle.

This is an unusual pairing mostly due to color and activity levels. As long as temperatures match and there is room to swim, Boesemani rainbows can live alongside zebras.

12. Cherry Barbs

Cherry Barb

A popular freshwater fish from the barb family. One of the most peaceful barb fish

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- Scientific Name: Puntius titteya
- Tank Size: 25 gallons
- Adult Size: 2 inches
- Water Temperature: 73. 81° F
- Temperament: Peaceful, sometimes shy
Cherry barbs are one of the most ideal tank mates for zebras! Similar in size and activity, these two fish can comfortably live together as cherry barbs prefer the lower areas of the tank.

That being said, these small barbs can sometimes be shy fish. It’s best to keep these fish in a larger densely planted tank with a good-size school. They can be somewhat sensitive to water parameters, so they should be safely acclimated and kept with good tank husbandry.

13. Hatchet Fish
- Scientific Name: Gasteropelecus sternicla
- Tank Size: 20 gallons
- Adult Size: 2-3 inches
- Water Temperature: 72-81° F
- Temperament: Peaceful
If you’re looking for another fish to keep your zebra danios busy at the top of the tank, the hatchet fish will always be found just below the surface. While they don’t have the best vibrant colors, hatchet fish are one of the most interesting-looking fish species available!

These fish are great for community tanks but need a tight aquarium lid as they’re notorious jumpers.

14. Kuhli Loach

Kuhli Loach

Kuhli Loaches are hardy bottom-dwelling fish. Nocturnal in nature. Gets along with many fish and tolerate of coldwater environments

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- Scientific Name: Pangio kuhlii
- Tank Size: 20 gallons
- Adult Size: 3-4 inches
- Water Temperature: 73-86° F
- Temperament: Peaceful
No matter your tank setup, there is always room for a kuhli loach. These fish are incredibly silly and fit right in at the bottom of a community tank setup.

Kuhli loaches aren’t true schooling fish, but they thrive in the company of their own. It is important to take careful consideration when introducing kuhli loaches into community tanks as hobbyists sometimes keep them at higher-than-normal water temperatures.

Always make sure to keep an aquarium lid on to prevent your loaches from escaping!

15. Platy Fish
- Scientific Name: Xiphophorus maculatus
- Tank Size: 10 gallons
- Adult Size: 2-3 inches
- Water Temperature: 64-77 °F
- Temperament: Peaceful, prolific
Platy fish are one of the most popular species of freshwater fish for beginner hobbyists and are one of the best tank mates for zebra danios. These community fish are colorful, active, and unbothered by other active species.

However, platy fish are incredibly prolific and can quickly overpopulate an aquarium. This, in addition to being overall messy fish, can cause water quality problems.

As long as populations and water quality are kept in check, then platy fish can comfortably live with zebra danios and an assortment of other fish!

16. Otocinclus

Otocinclus Catfish

A small algae-eating fish. Also great with freshwater shrimp.

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- Scientific Name: Otocinclus spp.
- Tank Size: 20 gallons
- Adult Size: 2-4 inches
- Water Temperature: 74-79°F
- Temperament: Peaceful, shy
Unlike the zebra danio, otocinclus are not beginner fish. In fact, these are some of the most difficult fish to keep due to their constant need for natural algae.

Otocinclus are smaller fish that rely on each other for safety. They need to be kept in groups of at least 6 or more and need an established aquarium with plenty of natural biofilm. A densely planted tank is a must.

Because these are some of the most challenging fish to keep and zebra danios are one of the easiest, these two species are not seen together often.

17. Cardinal Tetras

Cardinal Tetra

A very popular schooling fish. Looks like the Neon Tetra, but with longer blue and red stripes. Grows larger than a neon tetra as well

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- Scientific Name: Paracheirodon axelrodi
- Tank Size: 10 gallons
- Adult Size: 1-2 inches
- Water Temperature: 73-81° F
- Temperament: Peaceful
Slightly larger but more sensitive than neon tetras, cardinal tetras are great tank mates for danios. Cardinal tetras are colorful schooling fish that can be somewhat sensitive to both water quality and overactive tank mates. However, if they’re kept in a big enough school, they will feel safe to explore all corners of the tank, including where your zebra danios like to swim.

Cardinal tetras don’t have any special considerations, but they do best when acclimated and kept with live plants.

18. Honey Gourami

Honey Gourami

One of the more peaceful Gourami fish available in the hobby. Has a unique yellow coloration and only grows up to 2 inches in length

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- Scientific Name: Trichogaster chuna
- Tank Size: 10 gallons
- Adult Size: 2-3 inches
- Water Temperature: 74-82° F
- Temperament: Peaceful
The honey gourami is a great feature species for a zebra danio tank. These fish are big and bold but gentle giants. Honey gouramis can be kept alone or in pairs, as long as the tank size allows.

For the most part, the honey gourami makes a great tank mate for danios. Always make sure to keep an eye out for any potential fin-nipping between the two species. Zebra danios might take some interest in their thread-like pelvic fins.

19. Nerite Snails

Tiger Nerite Snails

These Nerite Snails will eat algae, are plant safe, and do not reproduce in your aquarium!

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- Scientific Name: Neritina spp.
- Tank Size: 10 gallons
- Adult Size: 1-2 inches
- Water Temperature: 65-85° F
- Temperament: Peaceful
If you don’t want to keep other fish with your danios, then nerite snails are ideal tank mates! These snails can’t reproduce in freshwater, so you don’t need to worry about them overpopulating. They are also efficient cleaners and will help keep the tank clean of any algae or uneaten food.

20. Bristle Nose Pleco

Bristlenose Pleco

The Bristlenose Pleco is a smaller Pleco that does a great job of eating algae. Peaceful and gets along with most fish

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- Scientific Name: Ancistrus cirrhosus
- Tank Size: 30 gallons
- Adult Size: 5 inches
- Water Temperature: 73-80°F
- Temperament: Peaceful
If you want a cleanup crew member that’s a little more exciting than a snail, then bristle nose plecos are a great addition to the freshwater aquarium. These plecos grow to reasonable sizes and don’t need a pure vegetation diet. Instead, they’ll help keep the tank clean of leftover food and other organic debris, though they won’t clean up fish waste.

21. Other Danios

If you’re a danio fan, then there are a few other species you can safely keep with your zebra danios. While there aren’t many species of danio available in the aquarium hobby, some of the most popular include:
- Giant danio (Devario aequipinnatus)
- Pearl danio (Danio albolineatus)
- Glowlight danio (Danio choprai)
- Blue danio (Danio kerri)
Apart from the giant danio, all of these species should have similar tank requirements, though exact specifications are needed.

Bad Selections

Though there are many great tank mates for zebra danios, there are a few that will never be compatible. Here are some species to avoid.

Bettas

Betta Fish” class=”wp-image-34308″/>

Betta fish are aggressive fish that need their space. The last thing a betta will tolerate is a zebra danio zooming around its territory.

These two fish are incompatible tank mates due to territorial aggression and overactivity of the Danio that will stress out the Betta.

Aggressive cichlids

Texas Cichlid” class=”wp-image-553069″/>

For the same reasons, zebra danios will never be compatible with aggressive cichlids, like most African Lake species. Not only will these cichlids see danios as a threat to their territory, but they’ll also see them as food.

Anything Big

That brings us to this next generalization. A zebra danio should never be kept with any species that could fit one of these small fish into its mouth.

A zebra danio can easily entice a predator as it zooms across the tank and be mistaken for food as a result. For this reason, it’s best to keep these danios with similar-sized tank mates.

FAQs

What fish can you keep with a zebra danio?

There are many fish that can be kept with zebra danios, but small tetras, rasboras, catfish, and loaches are some of the best choices! When picking a new fish for your zebra danio tank, water temperature and activity levels are the main factors to take into consideration.

How many zebra danios should be kept together?

These danios need to be kept in groups of at least 6 or more. Keeping less than this can cause individuals to become stressed out and reclusive. This might even lead to a premature death.

Are zebra danios good community fish?

Yes! Zebra danios are some of the best community fish available. These fish are extremely hardy and can be kept with most community species.

Are danios fin nippers?

Zebra danios can be fin nippers. It’s best to avoid long-finned tank mates or to increase the size of the school instead. This should help diffuse possible aggression.

Can danios go in a tropical tank?

Yes, zebra danios can be slowly acclimated to a warmer tank even though they prefer cooler temperatures.

Conclusion

Zebra danios are widely available fish. While they’re not the most colorful fish, they have bold stripes that catch the eye as they zoom across the tank. These fish are highly active and should be kept with tank mates that can tolerate their behavior. Luckily, many coldwater and freshwater species check this box!
February 24, 2024
How Long Do Fish Live? What I’ve Learned After 25 Years in the Hobby
After 25 years in this hobby, I’ve seen fish live surprisingly long lives. and heartbreakingly short ones. Koi are the most extreme example: there’s a famous koi named Hanako that was reportedly over 200 years old. But even in a home aquarium, the difference between a fish living 2 years versus 10 comes down to a handful of key factors. Diet and living conditions are the two biggest ones I’ve seen in my experience. In this guide I’ll break down the average lifespans of the most popular aquarium fish. and what actually determines how long they live.

How Long Do Fish Live (By Category)

There are over 30,000 fish species on the planet, ranging from tiny nano species to the majestic 60-foot whale shark¹. Their lifespans seem to vary as much as their size and appearance, with some species surviving just a few months and others living for centuries! Check our video above for visuals from our YouTube Channel. We go over in more detail in our blog post so you can follow along with both!

The average aquarium fish lives a few years with good care, although some species can live for a few decades. After reading this guide, you’ll see that there’s a lot of variation between the species.

Size And Growth

Unlike humans, fish are indeterminate growers, which means they continue to grow throughout their lives. It can be difficult to guess the age of a fish over at the pet store, but you can bet a large specimen has already reached a good age.

Scientists have a more precise way of judging a fish’s age. They simply count the rings on their scales, kind of like the way you tell the age of a tree². Unfortunately, there isn’t a lot of concrete scientific evidence about aquarium fish lifespans out there, so most of what we know comes from the experiences of other fish keepers.

Of course, many factors can affect how long fish live. For example, a fish that can live for ten years might survive just a few hours in a tank with incorrect water temperature, or it could surprise you and live for 12 years.

We’ll discuss some of the factors that affect fish longevity later in this post, but for now, let’s go ahead and dive into the average life expectancies of some popular aquarium fish you might consider keeping in your tanks.

Small Fish Lifespans

Smaller fish tend to have short lifespans, although some nano species can live surprisingly long! You could expect your pets to reach these lifespans with good care and a bit of luck:
- Betta fish/Siamese fighting fish: 2-4 years
- Cherry barb: 4-7 years
- Corydoras catfish: 5-15 years
- Danios: 2-5 years
- Dwarf pufferfish: 3-5 years
- Gouramis: 4-8 years
- Guppy: 2-3 years
- Hatchetfish: 2-5years
- Japanese Ricefish: 3-4 years
- Killifish: 1-3 years
- Kuhli loach: 10-14 years
- Neon Tetras: 2-5 years
- Otocinclus catfish: 5-8 years
- Rams: 2-3 years
- Rasboras: 5-8 years
- Platy: 3-4 years
- Scarlet badis: 3-6 years
- Tiger barbs: 4-6 years
- White Cloud Mountain minnow: 7 years
Medium Species

The average medium-size fish lifespan is between 5 and 15 years, which makes this group of fish a similar commitment to other popular pets like cats and dogs. Read on to learn about some popular medium aquarium fish lifespans.
- African Cichlids: 5-10+ years
- Angelfish: 10-12 years
- Blood Parrot: 5-15 years
- Blue Acara: 8-10 years
- Bristlenose pleco: 10-15 years
- Common Goldfish: 10-15 years
- Convict Cichlid: 8-10 years
- Discus cichlid: 10-18 years
- Fancy goldfish: 10-15 years
- Glass catfish: 7-8 years
- Jack Dempsey: 10-15 years
- Molly: 3-5 years
- Rainbowfish: 5-8 years
- Rainbow shark: 5-8 years
- Siamese Algae Eater: 5-10 years
- Silver dollar: 10 years
- Swordtails: 3-5 years
Large Species

Larger fish tend to live longer, although they need proper care and a suitable aquarium to reach their full potential. Let’s take a look at some big fish lifespans.

💡 A lifespan that still blows my mind: Koi are the most extraordinary example of fish longevity in the hobby. The famous koi Hanako was reportedly over 200 years old when she died in 1977. verified by scale ring analysis. Most koi in home ponds already live 25. 35 years with good care, which is remarkable for any fish. It’s a powerful reminder of just how much proper conditions matter.
- Arowana: 10-20 years
- Bala shark: 10 years
- Bichirs: 10-15 years
- Black ghost knife fish: 10-15 years
- Blood Parrot: 5-15 years
- Clown loach: 10-15 years
- Dojo loach/Weather loach: 10-15 years
- Flowerhorn cichlid: 8-12 years
- Koi fish: 25-35 years, but can over 60 years!
- Oscars cichlids: 10-15+ years
- Plecos: 10-20 years
- Red-tailed Catfish: 15-20 years
- Severum: 10 years
- Tinfoil Barb: 8-10 years
- Tire track eel: 8-18 years
Wild Species

Just in case you were wondering how aquarium fish stack up against wild species, here’s a list of some well-known wild fish and their lifespans:
- Atlantic Salmon: 5-8 years
- Bluegill Sunfish: 5-8 years
- Common Carp: 25-50 years
- Largemouth Bass: 10-15 years
- Rainbow Trout: 5-7 years
- Sturgeon: 50-60 years
Aquarium Invertebrates and Other Aquatic Animals

Fish are not the only animals that live in fish tanks! Continue reading to learn about some other aquatic pet lifespans.
- Cherry shrimp: 1-2 years
- Snails: 1-10 years
- Dwarf Frogs: 5-15 years
- Turtles: 20-40 years
- Axolotls: 10-15 years
9 Factors that Affect Fish Lifespans

The lifespans listed above are possible with good care and a healthy specimen, but tropical fish often live a much shorter lifespan than you might expect. There are many factors that can determine your pet’s longevity, and many of them are in your control as a fish keeper.

Continue reading to learn about nine factors that can increase or decrease aquarium fish longevity.

1. Age At Purchase

This one might seem pretty obvious, but young fish can live longer than old fish.

Most of the fish you see in the pet store are just a few months old, which means they still have most of their expected lifespan ahead of them. The large, mature specimens you see sometimes are much older, and it can be difficult to tell their age.

Young fish may be more fragile and susceptible to damage than mature specimens, but if you can get them through the acclimation period and the first few weeks in their new tank, these fish can survive for many years.

2. Stocking

Bullying and fighting between the fish in your tank can cause stressful living conditions and reduce your fish’s lifespan. Some fish tend to be more aggressive than others, and you really want to avoid these species when setting up a community tank.

I recommend stocking your tank with peaceful fish that grow to a similar size. This will also prevent any fish from getting snacked on. Remember, big fish eat little fish!

3. Physical Size

If you’ve already scanned through the list of fish and their lifespans, you probably noticed a general trend. Medium-sized fish live longer than small fish, and big fish live even longer.

Most small fish live about three to five years, while large species like koi can live for several decades. There are exceptions, of course. Kuhli loaches can live surprisingly long for their size!

Tank size can play an important role in fish lifespans too. Keeping large fish in a small tank will lead to cramped conditions, poor water quality, and a reduced life expectancy.

4. Genetic Factors And Fancy Breeds

Genetics plays a big role in the lifespans of pet fish. Some betta fish live for over four years, although selective breeding has decreased the average lifespan of some varieties.

Some fancy breeds tend to have shorter lifespans than wild-type fish. This applies to fish like balloon mollies and some fancy goldfish breeds. These fish may be more prone to health issues that affect their internal organs, but they can still lead a full and healthy life with good care.

5. Water Quality

Poor water quality is probably the leading cause of reduced lifespans in pet fish. Keeping a tank clean and maintaining a healthy environment can be tough for beginner fishkeepers, especially if you start with sensitive fish species.

Understanding the aquarium nitrogen cycle and testing your aquarium water regularly will help you maintain a suitable environment and keep your fish healthy, but having the right equipment is also crucial. Tropical fish need good filtration and regular aquarium maintenance to keep their water safe and achieve their full potential life span.

6. Water Parameters

Poor water quality is a major cause of fish mortality, but even well-maintained aquariums can be dangerous for some fish species.

Each fish species has evolved to live in a certain range of water chemistry parameters. Some fish are highly adaptable, while others won’t survive unless you recreate their preferred conditions. Of course, freshwater fish should not be mixed with saltwater fish and vice versa!

I suggest testing the pH level and water hardness of your local water supply before choosing your fish species. It is possible to alter your water chemistry or use bottled or reverse osmosis water in your tanks, but it’s always easiest to choose freshwater fish that will thrive in your local water.

7. Temperature

Incorrect water temperature can reduce fish lifespan to just hours, so this is one factor I really can’t stress enough. Tropical freshwater fish come from warm water habitats, so most fish keepers will need an aquarium heater to keep these fish healthy.

However, you probably won’t need a heater if you live in a tropical region, or keep your home at a constant temperature between about 75 and 80 degrees Fahrenheit. Fish temperature preferences vary depending on the species, so always research the needs of each individual fish species before adding them to a community tank with other fish.

8. Health Problems

Fish are susceptible to various illnesses that can reduce their lifespan. Common diseases include bacterial infections, fungal infections, viruses, and parasitic infections like ich that cause white spots.

Aquarium fish are most vulnerable to health problems when their water quality is low, but they can also develop illnesses when kept in unfavorable water parameters or with unsuitable tank mates.

Disease outbreaks can occur when you add a new fish to your aquarium, so it’s best to confine new fish to a quarantine tank before introducing them to your community aquarium. That way you can monitor your new pet fish for a few weeks and treat them with veterinary medicine if necessary.

9. Diet

Diet quality is another important factor that can increase or decrease your fish’s life expectancy. Different species of fish have different dietary needs, so you may need to provide more than one type of food if you keep multiple species of fish.

⚠️ The three mistakes I see most often that cut fish lifespans short: First, keeping fish in a tank that’s too small. chronic stress and stunted growth take years off their lives. Second, poor or monotonous diet. fish need variety and species-appropriate food to thrive. Third, bad tank mates that cause constant stress or injury. I’ve watched all three of these shorten the lives of fish that could have lived much, much longer.

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Modern prepared fish foods contain just about everything your fish need to stay healthy, but you can also supplement their diet with some healthy treats. Carnivorous and omnivorous fish love live or frozen foods like bloodworm and brine shrimp, while omnivorous and herbivorous fish species enjoy healthy snacks like peas and zucchini.

FAQs

How long does a pet fish live?

Depending on the species, most pet fish with live between 1 and 15 years with good care. The average nano fish will live between 3 and 5 years, while medium fish species have longer lifespans in the 5-15 year range.

How long do fish live naturally?

Fish in the wild probably live shorter lifespans than captive fish because they are exposed to more predators and dangerous environmental factors like floods, droughts, and cold snaps. Captive fish can live a surprisingly long life if kept in a clean tank with stable conditions and a high-quality diet.

Which fish species has the shortest lifespan?

According to the Guinness Book of Records, the fish with the shortest lifespan is the seven-figure pygmy goby. These tiny saltwater fish complete their entire life cycle in less than two months!

In the aquarium hobby, livebearers like guppies and platies tend to have shorter lifespans than similar-sized egg layers like the neon tetra. The average guppy has a lifespan of just two to three years.

Which fish live the longest?

The longest-living fish species is the Greenland shark, a species of deep, cold waters in the open ocean. These huge sharks can reach about 23 feet and live for over 400 years! This is one fish you probably don’t want in your home aquarium.

Which fish has the longest lifespan?

Goldfish are about the longest-living aquarium fish species, and some specimens will live over 25 years with proper care.

Koi can live even longer, although these beautiful fish from the carp family are usually housed outdoors in ponds. Their average lifespan is about 25 to 30 years, although one incredible specimen called Hanako is said to have lived for 226 years!

Final Thoughts

Fish lifespans vary between species, but you can use this guide to make a pretty educated guess about how long your fish will live. Of course, you’ll need to provide consistent care if you want your pets to reach their full potential, so check out my extensive range of fish care guides for loads of great advice!

How old is your oldest fish? Let me know in the comments below!

🐟 Want to learn more? This article is part of our complete Aquarium Care Guide. your ultimate resource for water chemistry, maintenance, feeding, disease prevention, and everything you need for a healthy tank.
February 18, 2024
Can Angelfish and Bettas Live Together? Why I Always Tell Customers to Avoid It
I’ve never personally attempted this combination. and after 25 years in the hobby, that’s a deliberate choice. I’ve heard the aftermath from customers who came into the fish store after things went sideways with this pairing. The core problem is size and temperament: angelfish are significantly larger than bettas, and while bettas have a reputation for aggression, they’re actually the ones that come off second best when an adult angelfish asserts itself. My advice: skip this combo entirely. This guide explains exactly why. and what to do if you’re already in this situation.
Key Takeaways
- Betta fish and angelfish are not recommended as tank mates.
- Some aquarists may have successfully housed these fish together in larger aquariums (55-gallon +) but it’s important to have a spare tank ready in case you notice any signs of aggression.
- Bettas can be aggressive, but they are slow swimmers and stay much smaller than angelfish, so they are more likely to be the victim in an aggressive encounter.
Can Angelfish And Bettas Live Together? – No!!!

Here’s your quick answer. In the vast majority of cases, Bettas cannot live with Angelfish in the same tank. Now that you know the answer, let’s go into why it doesn’t work.

Why It Doesn’t Work

Let’s take a look at some of the issues you’re likely to face.

Tank Size

On paper, angelfish and betta fish prefer similar water parameters, so you might think they make ideal tank mates. However, these fish have very different tank size requirements.

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You’ll need at least 20 gallons to house young angelfish and a 55 gallon tank for adults, but just 5 gallons or more to house bettas. So, you definitely can’t add angelfish to a small betta fish tank.

Aggression

Both angelfish and bettas can be aggressive fish, depending on their personalities. Both fish also have long fins, so they can be vulnerable to fin nipping.

However, a full grown angelfish is much larger than a betta fish, so if there’s any aggression, the betta is going to come off second best.

🚫 From my experience in the trade: This is the core of why the pairing fails. Bettas have a reputation as the aggressor, but next to a full-grown angelfish, that reputation doesn’t hold up. I’ve had customers come into the store after losing their betta to angelfish aggression they never saw coming. The size difference is just too significant. especially once the angelfish fully matures.

Angelfish can become especially aggressive during breeding, so if you have males and females, there’s even more risk of them harming your betta fish.

Illness

Aggression can turn your community tank into a toxic environment that is as stressful for you as it is for your fish. Unfortunately, aggression also causes illness and even death in pet fish.

A bullied fish often sustains minor injuries that leave them vulnerable to secondary infections. In some cases, aggressive betta fish or angelfish will even kill their victims outright!

Betta Basics

Betta fish (also known as Siamese fighting fish) are small freshwater fish that usually reach about 2.5 inches in length. Today, they are prized for their amazing colors and fancy fins, but these fish were once bred for competitive fighting.

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Bettas have a reputation for aggression, although they can make excellent community fish. A lot depends on their individual personality, but male bettas are likely to fight with their own species if housed in the same tank. It’s always safer to keep just one betta in its own aquarium, or with other compatible species.

Female bettas are generally regarded as less aggressive than males, although most fishkeepers choose males for their brighter colors and longer fins. You can learn much more about female bettas from my complete female betta care guide.

Betta fish live in shallow, freshwater habitats and have evolved to breathe air from the surface for survival¹. Their hardy nature means they can be kept in tanks as small as 5 gallons, although they require a filter and regular tank maintenance to provide good water quality. Bettas are tropical fish so they also need heated water to stay active and healthy.

Check out my guide to 15 betta fish tank mates (and four to avoid) for advice on some great freshwater fish that can share a tank with a Siamese fighter!

Facts and Figures
- Scientific name: Betta splendens
- Fish family: Osphronemidae
- Origin: Southeast Asia
- Diet: Carnivore
- Temperature: Upper 70s to mid 80s Fahrenheit
- pH: 6.8 – 7.5
- Hardness: Soft
Angelfish in a Nutshell

Angelfish are medium-sized South American fish from the cichlid family. These popular fish come in various color forms, but each breed has that characteristic combination of long dorsal and anal fins.

These fins make the angelfish very ‘tall’, so it’s best to keep these freshwater fish in an aquarium with high sides. In terms of size, these fish can reach over 6 inches in length and an impressive 10 inches in height, so a single fish will need a tank of at least 20 gallons, with 55 gallons being better for larger adults.

While angelfish are relatively peaceful, they are cichlids, and they aren’t always complete angels! These fish are typically classified as semi-aggressive but they can be pretty aggressive when they’re paired up and start breeding.

Freshwater angelfish are omnivores, and they have a pretty small mouth. However, they will eat nano fish small enough to swallow.

Looking for some great ideas for angelfish tank mates? Check out my guide to 15 freshwater species that get along with angelfish!

Facts and Figures:
- Scientific name: Pterophyllum scalare
- Fish family: Cichlid family
- Origin: Amazon river basin in South America
- Diet: Omnivore
- Temperature: Upper 70s to lower 80s Fahrenheit
- pH: 6.8 – 7.8
- Hardness: Soft
How To Keep the Peace

If you already have angelfish and betta fish in the same tank, there are some things you can do to decrease the chance of aggression. Again, there are no guarantees, but a combination of these techniques might help prevent war in your aquarium.

Go Big

A lot of compatibility problems are caused by keeping fish in small tanks. When it comes to angelfish and betta fish, your chance of success rises as you get into that 55+ gallon range, but remember, these fish are still not recommended as tank mates. You have safer bets in 6 or 8 foot long tanks, but at that size your Betta will get lost in the visual of the display tank.

Get the Parameters Right

Fortunately, bettas and angelfish thrive in similar conditions. Aim for a water temperature in the upper 70s Fahrenheit and a neutral pH around 7 to keep both fish happy. Both angelfish and betta fish prefer water with a low flow, so use an appropriate filter.

Start With Young Fish

Young angelfish do not have the same territorial and aggressive drive as breeding adults, so they’re often safer to keep together with bettas. Letting your fish grow up together might also help prevent aggression down the line, but you can still expect some dominance battles as they grow and reach maturity.

Female Bettas and Single Angelfish

Female bettas are generally less aggressive than males, and their shorter fins are less prone to damage. Paired angelfish can be more aggressive than single specimens, so a combination of one or more female bettas and a single angelfish might work the best, especially when combined with some of the other tips mentioned here.

Monitor Regularly

You should check in on aquarium fish every day, but risky combinations like betta fish and angelfish should be observed frequently, especially in the weeks after they are introduced. A community tank with betta fish and angelfish should be positioned somewhere you can monitor it throughout the day.

Watch out for any signs of aggression so that you can take action before serious injury can happen. Aggression often takes place during feeding times, so be especially alert when your fish are eating.

Feeding Your Fish

Adding food to different parts of the tank at the same time can reduce competition and conflict, but you should also be aware that bettas and angelfish have slightly different diets.

Betta fish are mostly carnivorous and will thrive on a diet of prepared dried food and live/frozen foods. Angelfish are more omnivorous so they need a prepared food suitable for their needs.

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Live Plants

Live plants are beautiful to look at, fun to grow, and great for the health of your fish. They’re also perfect for breaking up the line of sight in the tank. This means fish are not always visible to each other, which reduces aggression. Large plants also provide hiding places where fish can escape if they feel threatened or are under attack.

Choose large plants like Amazon swords, vallisneria, and large Java ferns that will grow up into the water column, but don’t be afraid to add a few smaller species and floating plants to make your aquarium an even more natural environment.

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You can also use artificial plants, but avoid firm plastic decorations that can cut and damage your betta fish fins. Live plants are always better for bettas!

Caves And Structure

The hardscape in your tank can also play an important role in breaking up line of sight and creating hiding spots. Rocks, driftwood, cave ornaments, and other decorations provide places where fish can set up territories or hide from dominant tank mates.

Choose fish-safe ornaments that are made for aquariums to avoid introducing any chemicals into your tank. You should also check for any sharp edges that can tear your fish’s fins.

Dither Fish

Sometimes, the best way to avoid aggressive behaviors is to add more fish. Dither fish are active species that create movement and make it difficult for an aggressive fish to single out a victim. The best options are active schooling fish that swim at various levels in the tank.

Busy bottom dwellers like cory catfish, or fast, active fish like rainbowfish make good dither fish, but it’s important to choose other fish that enjoy the same parameters as angelfish and bettas. Avoid nano dither fish that are small enough for angelfish to swallow. You can also try medium sized social fish like molly fish.

Plan B – What To Do When War Breaks Out

If it doesn’t work out between your angelfish and betta, you’re going to have an animal welfare issue on your hands, and the best thing to do is separate your fish or find a new home for one of them.

You may already have a spare tank that you use for quarantining or treating sick fish, but if not, it’s always a good idea to have an emergency option. You could even use a bucket or something similar as a (very) temporary solution, just make sure the container has not been used to hold any toxic chemicals.

Once your fish are separated, it’s time to come up with a long-term solution. Continue reading to learn about three possible options.

Try A Tank Separator

Installing a tank divider will allow you to keep these two species in one aquarium without any drama, but it does limit the swimming space for both fish and all the other species in the tank. Fish tank dividers are available for sale, or you can make your own to save some money for your next tank.

✅ If you’re set on keeping both: A tank divider is the one scenario I can honestly endorse. It’s the only way to have both fish without risking conflict. That said, both fish will have reduced swimming space. so if you go this route, start with at least a 55-gallon tank so each side has enough room to live comfortably.

Budget Option

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With your fish separated in a single tank, you can start creating hiding spaces, adding more structure to break up their line of sight, and introducing live aquarium plants and dither fish.

If your fish still don’t get along after making some changes in the tank, you’re going to want to try one of these next options for a long-term solution.

Start A New Aquarium

Angelfish need much larger tanks than bettas, but you can create a great new home for a single betta fish in a tank as small as 5 gallons. This is usually the easiest and most cost-effective option, but it will limit your options for adding other species.

Male bettas are happy to live in their own tanks, but you’ll want to step up to a ten-gallon or larger if you plan on giving him some tank mates. Female betta fish can also be kept in their own tank, or you can keep a sorority of females in a larger aquarium.

There are great betta tank kits available, but you can also put your own tank together. Just don’t forget the heater and filter!

Starting a new tank is easier when you already have a cycled aquarium because you can seed your new filter with beneficial bacteria from the old tank to give the nitrogen cycle a jump start. However, you’ll still need to monitor your water parameters regularly, so keep that water test kit handy.

Check out my guide to fish-in cycling to make the transition as smooth as possible!

Rehoming

If your new angelfish isn’t getting along with your betta (or vice versa), and you don’t have the space for another aquarium, you might be able to return the fish to your local fish store. Call ahead and speak to someone at the store before taking your fish on another road trip.

Depending on their policy, you might not get a refund, but that’s still better than letting your fish get hurt. If the store has a no-return policy, you might want to ask any other fish keeping friends if they have space for a new fish or even put your pet up for sale to a good home.

Final Thoughts

So now you know why keeping angelfish and bettas together is a bad idea. Hopefully, you’ve also picked up some useful tips on how to keep the peace if you find yourself housing both species in the same tank.

While some fishkeepers have managed to keep these fish together successfully, I do not recommend trying it yourself. Rather check out my guides to angelfish tank mates and betta fish tank mates for some much safer options!

📘 Want to learn more? This article is part of our complete Betta Fish Guide. your ultimate resource for betta care, types, tank setup, feeding, tank mates, and more.

📘 Want to learn more? This article is part of our complete Freshwater Fish Guide. your ultimate resource for freshwater species, care tips, tank setup, and more.
February 18, 2024
Fish Tank Ideas: 30+ Setups That Have Inspired My Own Builds
I’ve been keeping fish for over 25 years, and few things in this hobby beat the moment a tank design truly clicks. Aquascapes, cichlid rockscapes, and nano planted betta tanks have all inspired setups in my own fishroom over the years. and they still do. If you’re looking for your next build or just some inspiration for what’s possible, this is one of my favorite topics to cover. Here are 30+ fish tank ideas from across the hobby that I keep coming back to.
Key Takeaways
- Designing an aquarium is a great chance to let your creativity run wild and create something truly unique. However, drawing some inspiration from other setups can be very helpful.
- Aquarium decorations are a great way to add some style and personality to your aquarium, but live plants and natural materials like wood are the best choice for nature-style fish tanks.
- Stick to hardscape and decorations designed specifically for aquariums. Natural decorations like rocks can be used if you clean them carefully, but some natural materials like sea shells and limestone can change your water chemistry.
- Be sure to include a filtration system if you’re creating a shrimp or fish tank, and a heater if you’re keeping tropical species.
- Don’t be afraid to think out of the box! Paludariums and emersed planted tanks are excellent aquarium ideas.
Nano Fish Tank Ideas

In the aquarium hobby, small aquariums are usually referred to as nano tanks. How small is small? Well, the definition varies, but you can call anything smaller than about 20 gallons a nano tank.

There are many different nano tank styles, ranging from species-only setups to thriving communities. Continue reading for some nano tank inspiration!

10-gallon Nano Betta Fish Tank Idea

Betta fish are one of the most popular nano fish in the hobby, but we see them in tiny bowls and other containers way too often. This beautiful 10-gallon nano betta fish tank deserves a round of applause¹!

The combination of live aquatic plants, driftwood, hardscape, and a little beach area gives this tank a feeling of balance and tranquility. I bet that’s one happy betta.

5-Gallon Betta Setup

You can also go a little smaller for a single betta, although you’ll still need a filtration system and a heater. Maintaining high water quality will also become more challenging, but regular water changes and cleaning will keep your fish happy and healthy.

At 5 gallons, this well-planned fish tank is about the smallest you should go for bettas or other live fish. However, you can make a nano tank look much roomier than it really is by decorating it carefully.

Notice how the dark substrate makes the plants stand out even more? Black sand or gravel can also make fish look brighter and it’s great for some shy fish species that prefer a dark habitat.

🏆 My Pick: If I had to recommend one starting point for beginners who want to build something beautiful without overwhelming themselves, it’s the natural planted betta tank. The footprint is small, the cost is manageable, and the results can look incredible. I’ve set up many of these over the years and they never get old. it’s the best entry point into seriously impressive aquarium design.

Community Aquarium

It is possible to keep multiple nano fish species together in a small tank, but you’ll need to step up to an aquarium in the 15 to 20-gallon range to house your fish safely.

This elegant tank is home to multiple fish species and some beautiful aquatic plants. Most fish that grow to about 2.5 inches or less can be kept in this tank size, although it’s important to research the minimum school size and parameters of each species.

Themed

There are some awesome aquarium decorations out there for setting up a themed fish tank. Check out these fun but contrasting examples from across the web!

Spongebob

Spongebob-themed aquarium decorations can turn a nano tank into a fun and exciting fish tank, especially for the kids. This themed aquarium looks just like a scene from the popular TV show, and those yellow fish fit right in!

Bamboo Forest

Looking for something a little more zen? Check out this peaceful betta tank, complete with its own bamboo forest. This fish tank theme is perfect for your work desk, especially if you have a stressful job.

Planted Aquariums

If you ask me, all freshwater aquariums should include some live plants! Live plants have many benefits for your fish, and they look great too! Let’s take a look at some amazing planted tank eye candy.

Submerged Bonsai

Plants dominate this incredible aquascape, although its creator has chosen to create a scene that looks more like a dry landscape than an underwater scene!

It would take many years to grow an actual bonsai that looks this good, but by cleverly planting a small plant like Anubias barteri var. nana on a great piece of driftwood, you can achieve much faster results.

The addition of carpet plants and that inviting clearing under the ‘tree’ make this peaceful scene really aesthetic. Can you picture a few shrimp or a betta hanging out under the shade of those branches?

Dutch Style

This amazing Dutch style planted fish tank ticks all the right boxes for aquarists who like a lot of color! This orderly aquascaping style requires dedication and a real eye for design, but the results are incredible.

⚠️ A Word of Caution: The biggest mistake I see people make when trying to recreate a tank they found online is skipping the research on plants and aquascape layout concepts. Aquascaping has its own language. rule of thirds, foreground/midground/background layers, plant selection based on light and CO2 requirements. If you dive in without understanding these principles first, you’ll spend a lot of money on plants that die and layouts that fall apart. Study the style you love before you buy anything.

The rimless tank and open-top design add another dimension of viewing pleasure to this tank. Sometimes, plants look the best when viewed from above!

Dutch-style planted tanks are all about the plants, but that doesn’t mean you can’t add some movement. The vertical bars on those angelfish really complement this tank!

Emersed Growth

There’s something special about a planted tank with emerging plants. This stunning aquarium is a true underwater paradise, complete with lush vegetation growing out of the water, just as it does in nature.

Many common aquarium plants, including Ludwigia and Rotala, can be grown emersed in a hoodless tank with suspended lighting.

Fish safety is an important consideration when planning an open-top fish tank. Fish are surprisingly good at jumping out of tanks, so it’s a good idea to cover the top with some kind of screen.

Paludariums

Giving your plants the freedom to grow up and out of the water creates a unique look, but you can go even further and create a truly amphibious tank. Paludariums, like this exquisite example, include an underwater section and a land section.

Depending on the size and design of your paludarium, you could house aquatic life like fish, shrimp like red cherry shrimp, or dwarf frogs in the water. The land section is great for frogs, and turtles that like to spend time in and out of the water.

The land section of your paludarium could take the form of an island that sticks out of the water in the center, or you could add a simple shelf, complete with some rocks, soil, and plants.

The Living Wall

A planted wall is another spectacular design, although this limits some of the animals you can keep. This example provides some swimming space for shrimp or nano fish, and plenty of planting space for those awesome tropical plants.

African Cichlids

African cichlid tanks are the ultimate choice for freshwater aquarists who want a large tank that bursts with color and movement. Although you can grow some plants in African cichlid tanks, these setups are usually all about the fish.

Rock Pile

Some fishkeepers house African cichlids in pretty open, bare-bottom fish tanks, but if you ask me, these fish look so much better with some dramatic rocky hardscape!

This tank creates wonderful cichlid habitats and makes a bold statement as a display tank. The white sand contrasts with the round rocks to make this simple but effective tank really pop.

Just make sure you secure round rocks properly if you set up a tank like this, they could easily injure your fish or crack your tank if they come tumbling down.

Rock Walls

When we talk about aquarium hardscape, most people think of arranging and stacking r o cks or driftwood on the bottom of the fish tank. However, the back and side walls can be used to create an amazing effect.

You could simply use a life-like stick-on aquarium background, or go this route and create something with real texture!

Angelfish

Ang elfish are stunning freshwater cichlids that come from South America. These distinctive fish have a very ‘tall’ body shape, so they need a tank with some real height.

These fish thrive in planted tanks and can be housed with many other peaceful community fish in a big enough aquarium – just avoid tiny tank mates that your angels might see as a tasty snack.

Altum Angel Aquarium

This gorgeous designer fish tank is home to a big group of Altum angelfish, a large species native to the Rio Negro and Orinoco rivers in South America. The dramatic driftwood contrasts against a backlit background to make an aquarium that no one is walking by without stopping to stare!

Aquascapes

Most aquascapes include live plants, but you can also create a stunning scene by arranging hardscape features like rocks and driftwood. Let’s take a look at some interesting aquascapes.

Forest Scapes

This inspiring aquascape looks just like a forest scene from the great outdoors, complete with mountains! This kind of project takes real dedication and a lot of experience, but the results are absolutely amazing.

Iwagumi

This iwagumi masterpiece by George Farmer highlights the simple beauty of this unique aquascape design. Each rock is carefully arranged in the frame to create a simplistic yet bold look, and the dense carpet of plants only adds to its appeal.

This type of fish tank looks best with a small group of schooling fish like neon tetras, which create the effect of a flock of birds flying over the aquascape.

The Nature Aquarium

This jaw-dropping tank is a prime example of a nature aquarium. The style was popularized by the legendary Takashi Amano, a pioneering aquascaper from Japan. The style aims to create a unique natural world, rather than recreating a scene directly from nature.

A variety of different plant types are used in this style, but hardscape features like rocks, roots, and driftwood are equally important in creating different zones and textures in the tank.

Glofish Tanks

Have you ever heard of Glofish? These neon-colored fish were originally genetically modified to identify toxins in water, but today they are very popular in the aquarium hobby for their vibrant colors.

Neon Glow

Glofish come in exotic colors like sunburst orange, electric green, and galactic purple, and they include popular species like corydoras catfish, tetras, danios, and rainbow sharks. These fish really stand out under blue LED lighting, and so do the special glofish gravels, aquarium decorations, and artificial plants.

Nano Glofish Setup

Glofish tanks are a perfect idea for the kid’s room or anyone who loves bright colors! This low-maintenance example shows off the amazing colors you can achieve with the right lighting and some cool glofish tetras.

Goldfish

The goldfish is another freshwater species that looks nothing like their wild ancestors. Hundreds of years of selective breeding have created the amazing variety of fancy goldfish breeds we know today.

Some people still think goldfish can live in little fish bowls, but these fish actually grow surprisingly large, so they need a fish tank of at least 30 gallons for long-term care.

Keeping goldfish is all about the fish. These adorable underwater pets have a long lifespan, and it’s really rewarding to watch them grow and thrive in a healthy fish tank.

The Minimalist

Many aquarists choose to keep their goldfish in open, minimalist tanks like this setup because they are easy to clean and place all the attention on the tank inhabitants. The addition of that long airstone adds another layer of interest to this fish tank while increasing oxygen levels in the water.

Eastern Elegance

This 60-gallon goldfish aquarium still has a low-maintenance design but includes a little more structure, including some great aquarium decorations that reflect the goldfish’s east Asian origins.

60 gallons is a great size for two or three fancy goldfish, and you could even consider some goldfish tank mates in a tank of this size.

Check out my guide to 11 goldfish tank mates for some great goldfish companions!

Nature Style Goldfish Aquarium

Unfortunately, goldfish love to snack on most plants, but that doesn’t mean you can’t create a natural home for your fishy friends. Some attractive river stones and soft artificial plants or tough live plants like Java fern and Anubias look great in a goldfish tank.

Big Tank Inspirations

Most of us can only dream of the kinds of tanks in this next section. Oh well, it doesn’t mean we can’t drool over them! Keep reading to learn about some amazing aquariums from across the world.

Outdoor Koi Pond with Glass Front

Don’t have space in your home for a big fish tank? These fish-lovers went ahead and designed a Koi tank/pond hybrid, which combines the best of both worlds!

Large koi are traditionally viewed from above, but this stylish setup allows you to enjoy your fish from every angle.

Kanye West’s Bathtub Aquarium

Stepping back inside, Kanye West’s super-stylish bath-tub tank is a great example of creative aquariums.

This tank helps you feel like you’re swimming in nature, every time you take a bath. The tank is filled with some awesome fancy goldfish.

The Mirage

Now, if money or space isn’t a problem, you might want to go with an aquarium like this beauty from the Mirage in Las Vegas. This mega 20,000-gallon fish tank is home to over 80 species of saltwater fish from tropical waters across the globe.

Atlantis The Palm

Some hotels go one step further, and let their guests view their amazing aquariums from within their suites! The Lost Chambers Aquarium in Atlantis Dubai allows viewers to enjoy sightings of over 60,000 ocean animals in the Ambassador Lagoon, all from their own suite!

Final Thoughts

So there you have it, 25 fantastic fish tank ideas that you can use to design your next aquarium. You could choose a nano-themed aquarium filled with cool decorations, an aesthetic nature aquascape full of aquatic life, or splash out on an impressive celebrity-style installation – the choice is yours!

Which of these 25 fish tank styles do you like the most? Share your view in the comments below!

🔧 Want to learn more? This article is part of our complete Aquarium Equipment & Gear Guide. your ultimate resource for filters, heaters, lights, pumps, tanks, and more.
February 17, 2024