Author: Mark Valderrama

I only kept Bala Sharks at the store — because they get massive and need far more space than most hobbyists realize. These aren’t typical community fish you can drop into a 55-gallon. They grow up to 14 inches, are semi-aggressive, and need to be kept in groups of at least five. A lot of people buy them as cute juveniles without understanding what they’re signing up for. If you can commit to the tank size and the school, though, they’re spectacular fish — and there are some great tank mates that genuinely work alongside them.

While these fish are not true sharks, they grow to some impressive sizes. It wasn’t until lately that hobbyists discovered the true care requirements that bala sharks have in the aquarium setting. If you’re able to properly house one of these monster freshwater fish, then you’ll need to consider some of the best tank mates.

The 15 Best Bala Shark Tank Mates

Such a large fish needs special consideration when choosing tank mates. Bala shark tank mates should be big, active, and able to withstand semi-aggressive and sometimes predatory behavior, especially during feeding times. All recommended minimum tank sizes have been adjusted to accommodate a school of bala sharks and other tank mates.

1. Other Bala Sharks

• Scientific Name: Balantiocheilus melanopterus
• Adult Size: 1-2 feet
• pH: 6.5-7.5
• Water Temperature: 72-82° F
• Minimum Tank Size: 125 gallons

The best tank mates for bala sharks are other bala sharks! You read that right, these fish do best when they’re kept with their own species.

⚠️ The Biggest Mistake With Bala Sharks: Most people don’t realize what they’re committing to when they buy juveniles. Bala Sharks are semi-aggressive, need a group of at least 5 to feel secure and behave properly, and grow large enough that adults need a 150+ gallon tank. I only kept them at the store for exactly this reason — they’re not practical for most home setups. If you can’t commit to both the school size and the tank space, this is the wrong fish.

While widely available, bala sharks actually come from pretty unique ecosystems where other freshwater aquarium fish aren’t regularly collected. Instead, other monster fish, like the iridescent shark (Pangasianodon hypophthalmus), are collected and kept in extremely large systems or public aquariums. This can make it difficult to pair bala sharks with other endemic species.

Bala sharks also enjoy the company of each other. They can be shy and skittish when the only shark in the tank, and being in the company of others increases their confidence. Keep in mind that an overly bold bala shark can become semi-aggressive and might even try to eat smaller fish.

2. Gouramis

• Scientific Name: Helostomatidae family/Osphronemidae family
• Adult Size: 6-20 inches
• pH: 6.5-7.5
• Water Temperature: 72-82° F
• Minimum Tank Size: 125-250 gallons

Dwarf gouramis (Trichogaster lalius) are some of the most popular fish to keep in community tanks. We’re going to need something a little bigger than a dwarf gourami, though.

There are many species of gourami, some of which grow to extreme sizes, making them a great bala shark tank mate! Two of these species are kissing gouramis and giant gouramis.

Kissing gouramis (Helostoma temminckii) are not usually recommended for community fish tanks but make suitable tank mates for bala sharks. Kissing gouramis can be somewhat territorial, so it’s best to keep your bala sharks in decently sized schools and provide plenty of hiding spots.

The giant gourami (Osphronemus goramy) is a huge fish that requires at least 250 gallons. While these fish are often slow and sluggish and unlikely to chase after more active swimmers, like the bala shark, they may defend their territory if needed. Because of this, it’s best to keep the bala sharks in larger numbers and with plenty of rocks and decorations.

3. Angelfish

• Scientific Name: Pterophyllum spp.
• Adult Size: 4-6 inches
• pH: 6.0-7.5
• Water Temperature: 75-82° F
• Minimum Tank Size: 125 gallons

Angelfish are a very popular option as bala shark tank mates. Though bala sharks are active swimmers and angelfish are not, these two species seem to balance each other out. As a result, the angelfish and bala sharks will typically start to float and swim together in the middle of the water column.

There are many species of angelfish available. The common Pterophyllum scalare can reach a large enough size to complement a bala’s length. These fish come in nearly every color combination, which can accent the shine of the sharks. If you’re looking for a real fishkeeping challenge, then you may opt for the expensive and difficult-to-keep altum angel (Pterophyllum altum), which also grow to larger sizes.

Angelfish do best when kept in small groups of the same species. If planning to keep larger species of angel, then it’s recommended to have at least a 150 gallon aquarium.

4. Clown Loach

• Scientific Name: Chromobotia macracantha
• Adult Size: 1 foot
• pH: 6.0-7.5
• Water Temperature: 72-82° F
• Minimum Tank Size: 125 gallons

One of the most common tank mates for bala sharks is the clown loach. For decades, these fish were kept in overly small community tanks where they couldn’t thrive. While care requirement understanding has changed for these two different species, it’s still agreed that they make a great tank mate pairing.

Clown loaches have very similar temperaments to bala sharks and can grow to relatively the same size. In addition, clown loaches are schooling fish which will help shyer bala sharks come out to the front of the tank.

While clown loaches might seem like smaller fish, they can still grow to be a foot in length. They originate from fast-flowing rivers and need good water circulation, but not so much that your bala shark school gets pushed around the aquarium.

5. Blood Parrot Cichlid

• Scientific Name: Cichlidae hybrid
• Adult Size: 6-10 inches
• pH: 6.5-7.5
• Water Temperature: 75-82° F
• Minimum Tank Size: 125 gallons

Blood parrots are a hybrid type of cichlid. This means that they can sometimes display aggressive behavior towards overly active or small fish; an especially large blood parrot cichlid may also try to eat smaller fish. Because of this, it’s recommended to only keep appropriately sized bala sharks with these fish.

Otherwise, a blood parrot cichlid will bring a ton of color to a bala shark tank. They are not overly active swimmers, which can help calm shy and skittish bala sharks.

It should be also noted that, because they’re hybrids, blood parrot size can greatly vary. It’s better to go with a larger tank than necessary, not only to allow for potential size and bioload but also to safely keep multiple parrots with multiple sharks.

6. Severum

• Scientific Name: Heros severus
• Adult Size: 6-10 inches
• pH: 6.0-7.5
• Water Temperature: 72-82° F
• Minimum Tank Size: 125 gallons

A true species of cichlid, severums are one of the most popular fish to keep in the freshwater aquarium and make good tank mates for bala sharks. Severums are a relatively peaceful species of South American cichlid. They are much more forgiving of other fish than most cichlids.

However, multiple severums do not do well when placed together in the same tank, especially if the aquarium is small. In certain settings, breeding pairs of severums can be safely kept. Bala sharks are probably too active for a pair of severums aggressively defending their nest and territory, though. For this reason, we only recommend keeping one severum alongside bala sharks.

7. Geophagus Cichlids

• Scientific Name: Geophagus spp.
• Adult Size: 6-8 inches
• pH: 5.5-7.5
• Water Temperature: 72-82° F
• Minimum Tank Size: 125 gallons

Another South American cichlid, geophagus are natural-looking fish that can vary in appearance. These fish are mostly a mixture of silvers, blues, and greens, with males being more colorful and ornate than females.

Along with appearance, aggression can vary with geophagus species. It is believed that Geophagus altifrons is one of the least aggressive species available. These fish enjoy their own species and being in schools of at least 6 or more, but some hobbyists have kept multiple species together in the same tank as long as space allows.

8. Tinfoil Barbs

• Scientific Name: Barbonymus schwanefeldii
• Adult Size: 1-1.5 feet
• pH: 6.5-7.0
• Water Temperature: 72-82° F
• Minimum Tank Size: 150 gallons

Tinfoil barbs are very large barbs from Southeast Asia. These fish are not commonly seen available in the normal freshwater fish hobby but are a favorite among monster fishkeepers. These fish grow to extreme sizes as a barb species, and feature a simple silver color with black and red angular fins.

Tinfoil barbs are schooling fish and need to be kept in groups of at least 6 or more. Because bala sharks are also schoolers and share a similar demeanor, an especially large tank is needed. If keeping only these two species, then a 150 gallon is needed. Keeping different species would require a several hundred gallon system.

9. Tiger Barbs

• Scientific Name: Puntigrus tetrazona
• Adult Size: 2-4 inches
• pH: 6.0-7.0
• Water Temperature: 72-82° F
• Minimum Tank Size: 125 gallons

In addition to the clown loach and bala shark pairing, the tiger barb and bala shark aquarium setup was inescapable for years. Tiger barbs are a very popular community tank shoaling fish and do best when kept in groups of at least 6 or more. Since bala sharks need a large aquarium, hobbyists can easily fit dozens of barbs in a 125 gallon system while still allowing for other species as well.

It should be noted that tiger barbs can be especially nippy and might try to chase and harass slower-moving fish. For the most part, bala sharks should be able to outpower and navigate around, especially feisty barbs, but additional protection through plants and structures will help keep aggression down.

🏆 My Top Pick: Tiger Barbs are my go-to recommendation for a Bala Shark tank. They’re large enough not to be eaten, active enough to match the Bala’s energy, and this pairing has been a staple in the hobby for decades for good reason. Keep your Tiger Barbs in a school of 6+ and their nippy behavior stays in check — a big group keeps them focused on each other rather than harassing tank mates.

10. Boesemani Rainbowfish

• Scientific Name: Melanotaenia boesemani
• Adult Size: 3-5 inches
• pH: 7.0-8.0
• Water Temperature: 72-82° F
• Minimum Tank Size: 125 gallons

Bosemani rainbowfish are very different in comparison to bala sharks by way of appearance, natural habitat, and behavior, but this unusual pairing seems to work. In general, bosemani are a larger species of tropical fish that fills an aquarium with bright colors and movement. This is in contrast to slow but steady iridescent bala sharks.

There is one consideration that needs to be taken when keeping bosemani rainbowfish as tank mates, though, and that is that they enjoy slightly harder and more basic water parameters. As long as both the bala sharks and bosemani rainbows have been kept in standard aquarium water conditions, then there should be no need for acclimation. You can also check out Emerald Rainbowfish as another option

11. Plecos

• Scientific Name: Hypostomus plecostomus
• Adult Size: 1-2 feet
• pH: 6.5-7.5
• Water Temperature: 75-82° F
• Minimum Tank Size: 150 gallons

We don’t usually recommend plecos as any tank mate option, but they do well in a large bala shark setup. Like bala sharks, common plecos have been long misunderstood fish regarding their behaviors and potential adult size. Plecos are huge fish that create a lot of waste! They can also easily injure and kill smaller fish by trying to suck the slime coat off their body.

For this reason, only one common pleco is recommended for a 150 gallon aquarium setup. While particularly aggressive plecos may still try to suck on the sides of bala sharks, balas will generally be faster and better protected in a school setting. Mid-sized plecos can also be considered.

12. Silver Dollars

• Scientific Name: Metynnis argenteus
• Adult Size: 6 inches
• pH: 5.0-7.0
• Water Temperature: 72-82° F
• Minimum Tank Size: 125 gallons

Though many species are regarded as a silver dollar, Metynnis argenteus is one of the most commonly available. Silver dollars are a comparable fish to the aforementioned tinfoil barb, though much, much smaller, and more manageable. These fish are pearlescent silver with some individuals showing hints of red on their anal fin.

Silver dollars are active schooling fish that will complement the same swimming patterns as bala sharks. Though only 6 inches wide, they can start to take up a decent amount of space as they grow vertically.

It should be noted that silver dollars are regularly kept in more acidic water parameters, so some acclimation might be necessary to keep them with balas.

13. Dennison Barbs

• Scientific Name: Sahyadria denisonii
• Adult Size: 4-6 inches
• pH: 6.5-8.0
• Water Temperature: 60-80° F
• Minimum Tank Size: 125 gallons

Dennison barbs are very popular tank mates for a variety of large fish species. They are colorful, active, and get along with most other fish. Unfortunately, these fish originate from very particular ecosystems throughout India, and their numbers are dwindling. All efforts should be made to replicate their natural settings in the home aquarium, including a high rate of water flow.

Otherwise, Dennison barbs thrive in groups of at least 6 or more. They are moderately active swimmers and can become slightly aggressive during feeding times. While they should be completely compatible with bala sharks, some care should be taken to ensure your sharks get enough to eat.

14. Pictus Catfish

• Scientific Name: Pimelodus pictus
• Adult Size: 3-6 inches
• pH: 6.5-7.5
• Water Temperature: 75-82° F
• Minimum Tank Size: 125 gallons

If you’re not looking for a bottom-dwelling fish as big as the common pleco, then the pictus catfish might offer something smaller and more eye-catching. These fish are silvery-white with assorted black spots across their bodies and fins. They also feature three sets of barbels.

The pictus catfish is one of the most ideal tank mates for a bala shark aquarium as they are largely nocturnal, swim at a different water column level, and complement the natural colors of the sharks. They also stay much smaller than other similar catfish, though they will need to be kept in small groups of at least 3 or more.

15. Giant Danios

• Scientific Name: Devario aequipinnatus
• Adult Size: 3-5 inches
• pH: 6.0-7.0
• Water Temperature: 72-82° F
• Minimum Tank Size: 150 gallons

The giant danio is becoming an ever-increasing popular fish in the aquarium hobby. They should not be confused with the readily available zebra danio (Danio rerio) as these fish require tropical temperatures and a larger tank.

That being said, giant danios are still very active schooling fish that can easily overwhelm smaller fish. Unlike zebra danios, they swim toward the middle of the water column, where bala sharks also prefer. To make this pairing work, the danios should be overall smaller and in a smaller group size than the sharks.

Aquatic Animals To Avoid

Though bala sharks might be afraid of their own shadow, there are a few fish and invertebrates they won’t be compatible with. Even though bala sharks are relatively hardy fish, they do have some special considerations.

1. Shrimp

Shrimp are great cleanup crew members and can bring color and life to the bottom of the aquarium. Sadly, they are not good tank mates for bala sharks and will be easily eaten instead.

2. Small Snails

For the most part, bala sharks won’t eat mature snails. However, they might be tempted to eat a snail that is smaller than their mouth. For this reason, only large, full-grown snails should be kept as tank mates for bala sharks.

3. Small Fish

For the same reasons, bala sharks should not be kept with fish that are smaller than their mouth. While bala sharks are not overtly aggressive fish, they will not hesitate to try to eat anything that they can.

4. Aggressive fish

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Again, bala sharks are not overly aggressive and they will be harassed and outcompeted by a larger, more aggressive, and more active tank mate. These fish are naturally shy and will not defend themselves if they are attacked by another fish.

Their Care Requirements

While we talked about possible tank mates, we also need to go over the intense requirements of bala sharks. For a long time, bala sharks have been kept in relatively small aquariums due to their unassuming juvenile size and striking appearance. The truth is that bala sharks can grow to be 1-2 feet long!

The bala shark (Balantiocheilus melanopterus) is a slender freshwater fish with pointed fins that resemble those of a marine shark. They have been documented in the Mekong River basin, as well as throughout the Malay Peninsula, Sumatra, and Borneo. Unfortunately, populations are dwindling in their natural habitat.

As of yet, bala sharks have not been, or are very rarely, bred in the aquarium setting. This means that wild-caught individuals need to be preserved in aquariums that fit their needs. Keep in mind that bala sharks are schooling fish and do best in groups of at least 3 or more. Because of this and their mature size, bala sharks require at least a 125 gallon aquarium, with a longer footprint being better than a tall one.

Want to learn more about their requirements in detail. Check out our care guide here.

FAQs

Final Thoughts

The art of keeping bala sharks has long been misunderstood. These are relatively peaceful fish that grow to large sizes and therefore, need a large aquarium setup. That being said, they can comfortably be kept with a variety of other freshwater fish as long as they don’t fit inside your shark’s mouth and aren’t overly active.

One of my favorite things about bettas is how expressive they are — even when they’re sleeping. Over the years I’ve watched them tuck under floating plants, wedge into tank corners, or prop themselves on a little leaf hammock completely motionless. I’ve had more than a few customers call me convinced their fish had died overnight, only to find out it was just resting. Bettas are remarkably good at going completely still when they sleep. Here’s what you actually need to know about when, where, and how they do it.

How Do Betta Fish Sleep?

Like all living organisms, betta fish need sleep to function properly¹. But of course, the way they sleep is far different than that of humans and other land animals because… well, they live in the sea with no beds, covers, or eyelids. 

Though, the Siamese fighting fish are diurnal animals; they sleep at night and are active during the day—they may take short naps during the day for a few minutes. During nap time, Betta fish usually sleep near the bottom of the tank or on a flat surface, mainly on a plant or substrate. Also, unlike many fish, betta don’t have eyelids, so their eyes remain open when betta are sleeping. 

Since we know that betta fish is a labyrinth fish with a special organ that allows easy breathing on the surface, you may also find them resting near the water’s surface or between floating plants, sleeping in a tilted position. 

🏆 Mark’s Observation: In my experience, bettas strongly prefer sleeping under floating plants or on a leaf hammock placed near the surface — they feel secure with something above them. If your betta doesn’t have either, add a betta hammock or some floating plants like frogbit or water lettuce. You’ll notice a real difference in how settled and relaxed they look at rest. It’s one of the easiest improvements you can make for their wellbeing.

However, if your betta fish is spending too much time on their side or in any one direction, make sure it doesn’t have any underlying medical condition. 

All in all, the sight of betta fish sleeping is beautiful and allows you to study your fish’s own sleeping habits and preferences. Some betta fish like to rest in a particular spot or position while some enjoy various sleeping locations. Therefore, it is important to provide your betta fish with a comfortable environment with lots of hiding spots.

Sleeping Or Sick? – How To Tell If They Are

Not sure whether your betta fish is sleeping or sick? Here are some of the ways you can find out if your betta is sleeping. 

Gill flaring

One of the most peculiar behaviors of betta fish is gill flaring which attracts many betta owners and other aquarists. Betta fish flare their gills for a variety of reasons. However, a sleeping betta fish might temporarily cease the gill flaring behavior to preserve energy while at rest. 

Therefore, if you notice minimal or record gill flaring, know that your betta is taking its power nap!

Breathing rate

One of the most common signs your betta is sleeping is the slowed breathing rate with shallower breathing patterns.

Reduced body movement and activity levels

Like other fish, a sleeping fish tend to move slowly for extended periods of time. Therefore, they show minimal movement and interaction. If you’re a new betta owner, you may find your fish resting with no movement and activity levels. Fret not! They are not dead, just sleeping. 

How Long Do They Rest?

Like every human, every individual betta fish is different than others. Therefore, there is no one answer to “How long do betta fish sleep?”

However, betta fish are diurnal animals i.e., they are active throughout the day and sleep at night. Therefore, if you find a betta sleeping a lot during the time, it is not normal behavior and could be a sign of disease or other problems.

On average, betta fish sleep between 8 to 12 hours a day.

Why Do Bettas Rest A Lot?

Picture yourself swimming wearing a big, flared dress non-stop! Sounds tiring, doesn’t it?

The same goes for betta fish. They have such long, flared beautiful wings that it gets tiring to carry them swimming around the fish tank. Therefore, betta fish, in general, fall under the lazy spectrum because they take longer periods of rest and sleep than their counterparts. 

Just like betta fish, many varieties of goldfish with long fins and stout compact bodies also take significant time resting in the aquarium.

Therefore, if your water parameters; water flow, and water temperature are within the ideal ranges, the inactivity of your fish is nothing serious. For your betta fish to thrive in your aquarium, the ideal water temperature should be between 78-82F since they are tropical fish and prefer warmer temperatures. If your water is too cold for their liking, bettas sleep more than usual because of slower metabolism and may suffer from health issues.

Reasons why your Betta Fish is Sleeping a lot

If you find your betta fish sleeping a lot during the day time, there can a various reasons:

No Stimulation

It would surprise you but your little guy in the tank gets bored too. And yes, they need a little stimulation activities. You might also try some fish training techniques. In short, if your betta is sleeping a lot, they might just be bored and need a little loving to be active again. 

Aquarium lights

Betta fish sleep throughout the night. Therefore, if you leave aquarium lights on during the night, they may disturb the natural sleep pattern of your fish and result in abnormal sleep cycles. Betta loves dark tanks, especially during the nighttime time because their natural habitat is dark and shallow with little water movement. Therefore, it’s crucial to mimic their natural habitat for their better health. 

A healthy betta fish needs at least 12 hours of complete darkness each night in a comfortable environment to promote healthy sleep patterns.

⚠️ Three Things That Make or Break Betta Sleep: First, consistent lighting — use a timer for 10-12 hours on, 12-14 hours off, every day. Second, hiding spots near the surface (hammocks, floating plants) so they feel secure enough to fully relax. Third, stable temperature — a drop below 76°F can trigger lethargy that looks like sleep but is actually temperature stress. Get all three right and you’ll have a noticeably more active, healthy fish.

Temperature shock 

Many aquarists have a misunderstanding that betta fish hibernate. When in reality, they go into temperature shock if the temperature drops below a certain mark since they are tropical fish.

As a result, they may look like they are sleeping fish, but what actually happens is their metabolism slows down and causes temperature shock. Therefore, maintaining a comfortable water temperature is essential to keeping your betta fish healthy, happy, and thriving in an aquarium setting. 

How to Stop Excessive Resting?

Here are a few things you can do to stop reducing your bettas sleeping time. 

1. Make sure the temperature in your tank is within the comfortable range; of 78-82F. If not, you can always install a heater to keep the water warm and easy for your betta fish. I also recommend using an in-tank thermometer for reliable temperature readings.
2. Besides maintaining the water temperature and water flow, it is crucial to feed a varied diet consisting of live food, frozen food, pellets, and other occasional treats for a complete nutritional profile. 
3. Last, but not least, always call your aquatic veterinarian for a careful examination of your betta fish. The most common fish diseases include mycobacteria and swim bladder disease may cause your fish to be more lazy and lethargic. 

How To Distinguish Between a Sleeping Pet and a Dead One

If you ever spot a betta fish floating on the top of your tank or lying on the bottom of the tank, fret not!

They might just be sleeping… but in some cases, you might mistake a dead betta fish with a sleeping betta fish. Therefore, it’s important to pinpoint the differences between the two. Here are some of the signs of a dead betta fish you should look out for:

1. If your betta fish stays at the bottom of the tank for several days, chances are they are dead. However, if they have just settled recently, they might just be sleeping peacefully.
2. If the scales seem pointy and elevated away from the body with a swollen stomach, your betta fish might be just or is near death. 
3. There are white spots around the body with discolored fins. You can use a flashlight to observe the color carefully.
4. When they don’t even respond during the feed time and are not interested in food. 

It is crucial to let your betta fish rest. However, if you find your fish lying motionless for long periods, examine the gills and mouth carefully and observe its breathing patterns. If your betta fish is not breathing and moving, know that it’s dead.

FAQs

Final Thoughts

Betta fish keeping as a leisure hobby is increasing day by day, but taking care of your bettas’ sleep is one way to keep them healthy and active. Other than their diet, water parameters, and water flow, you should also consider keeping your tank clean and taking care of their tank mates. Always go for compatible tank mates such as mystery snails, shrimps, and guppies to reduce stress and increase interactivity. 

A betta tank should be well-lit in the daytime and dark throughout the night, so they get enough sleep since they are very light sleepers. 

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📘 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.

I dealt with Columnaris more times than I can count during my years running the local fish store. Customers would come in with a fish showing what looked like mild fin damage or a pale patch near the dorsal — and if we weren’t fast about it, that fish would be gone within 24 to 48 hours. I’ve personally cured fish with this exact protocol, and the one thing I always told people: don’t make the mistake of treating this like an ordinary bacterial infection that a basic salt dip will handle. Columnaris is aggressive, it spreads fast, and it requires a focused, multi-step approach. Here’s exactly what I do.

Before You Get Started

• Aquarium salt
• Antibiotic medications – Methylene blue or Triple Sulfa (if available in your country)
• Thermometer (To measure tank temperature)
• Quarantine Tank (if available)

How To Cure Columnaris: A Step By Step Guide

Step 1 – Quarantine The Fish

While it is certainly possible to treat the fish inside your display tank, my preference is to treat them in a quarantine tank.  If you cannot set up a quarantine tank in time, you’ll need to treat in the display tank. Note that Methlene blue is known to stain silicone and will affect your system’s beneficial bacteria, which is why I prefer to quarantine.

If you do not quarantine the fish, you should do a 50% water change before any treatment occurs. This will ensure you have ideal water parameters before you add any medications.

In all my years treating Columnaris in-store and at home, quarantine was the single biggest factor in whether a fish survived or not. I always told customers: set up a spare 10-gallon with a sponge filter before you ever need it — not when a fish is already showing symptoms. Once Columnaris gets going, every hour counts. A QT tank that’s already cycled and ready the moment you spot something is the difference between a recoverable situation and watching a fish decline rapidly.

Step 2 – Treat The Tank With Salt

You will need to dose the tank with salt. You’ll need to be quite liberal with the dosage and amp it up to 2 and half tablespoons per gallon or 3 cups per 20 gallons. This is a lot of salt and will harm any plants in the tank. Note that some fish like Plecos are sensitive to salt so you will need to take caution with them. Some snails and shrimp are also not tolerate of salt treatment.

One mistake I see over and over: a hobbyist spots a sick fish, reaches for aquarium salt, doses the tank, and waits. With most freshwater bacterial infections, salt alone goes a long way. Columnaris is not that type of disease. Salt is only one component of a three-part protocol — without quarantine, temperature reduction, and Methylene Blue all working together, you are not treating this infection effectively, and the fish will most likely not survive.

Step 3 – Dose With Methylene Blue

When antibiotics like Triple sulfa were available, this would have been my go to. However, since it is no longer available in the US and is hard to find (and expensive), my recommendation is to use Methylene Blue. While this is primarily used to treat fungal diseases, it is also effective for this treatment procedure because it acts as a disinfectant. Use the recommended dosage as stated on the manufacturer’s bottle

Step 4 – Lower Water Temperature

Columnaris spreads rapidly in higher water temperatures. Therefore, lowering the temperature might help. You want to target a temperature of 70 – 72 degrees Fahrenheit.

However, if your fish is accustomed to higher temperatures, it will take some time to adjust to temperature changes. Thus, I recommend lowering the temperature by only 2F every two hours.

Step 5 – Monitor Water Quality And Observe

Columnaris bacteria thrive on organic waste. Therefore, it is essential to keep your tank clean and maintain the recommended water parameters for your fish. Check your water for ammonia, nitrate, nitrite, KH, and GH, and ensure nothing is affecting your fish adversely.

The observation period for this treatment is 7-10 days. In most cases, if the fish survives, the fish should be cured of columnaris and it should be eliminated from the tank. Anything you use in this tank that is untreated, you will want to sterilize. A solution of bleach or dry out for several days will kill off any remaining infection.

What To Avoid Doing

• Don’t ignore the condition – treat it quickly. Don’t wait around!
• Avoid doing water changes. If a water change is made, you will need to re-dose the tank
• Do not carelessly add fish afterward, consider a quarantine process for new additions going forward to prevent recontamination.

What To Do If Symptoms Are Still Around After 10 Days?

If the infection is stubborn, it’s time to go with a half dosage of meth blue and salt. This is an extreme dosage. Either this will eliminate the disease or your fish will end up passing away. Treatment after 10 days tends to have a low success rate, and we get into a worse case scenario.

Note that this technique I outline does not use antibiotics. There are methods where you can, but I preferred for this post not to include them because the ideal medication isn’t available in the US and this method does have a high success rate.

How To Prevent It

As mentioned earlier, the Columnaris bacteria thrive on organic waste. Therefore, partial water changes every two weeks and regularly test water chemistry to ensure recommended water parameters are some of the best ways to keep the bacterial infection at bay. 

Furthermore, the immune system of your fish should be healthy and strong enough to fight off the bacteria. Strong immunity is a result of eliminating stress factors such as bullying and harassment or water fluctuations from your aquarium. It is also recommended to clean up the fish waste and decaying plant matter and gravel to foster a hygienic environment for your fish. 

Also, overcrowding, tank size, and tank mates should be taken into consideration because these factors directly impact the stress levels in your fish. Additionally, a balanced diet with occasional treats might help keep the infection at bay. 

What Exactly Is This Disease?

Columnaris disease is common among freshwater fish, particularly among livebearers fish such as guppy fish, Molly, etc. This disease is mainly caused by Columnaris bacteria that are long and rod-shaped; appearance-wise.

Name	Flexibacter columnaris
Common Treatments	Salt and antibiotics
Short-Term Treatment	Antibiotics
Causes	Transferred from infected fish, plants, and water
Treatment Time	7 – 10 days
Common Symptoms	Saddleback-like growth, lesions on body, mouth, infected gills

Columnaris disease is commonly known as saddleback disease, guppy disease, cotton wool disease, and cotton mouth disease. In brackish and saltwater the species Flexibacter maritimus is the equivalent and is more severe, though not common to see in aquariums.

What Are The Symptoms?

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Columnaris is often mistaken as a fungal infection because the fish might show signs of mold-like lesions on their bodies. However, Columnaris is caused by bacterial infection and forms lesions that progress gradually and end up killing the entire freshwater fish population in your tank, if left untreated.

Some of the common symptoms of Columnaris are:

1. Grey or white spots on the head, fins, and gills
2. Infected gill tissue
3. Lesions on the body
4. Lesions on the mouth area or puffy lips
5. Frayed, bleached out, and ragged fish’s fins

One of the first signs you’ll notice is frayed or ragged fins, commonly referred to as fin rot. However, not all fish experience fin rot and may show some other symptoms. For instance grayish or whitish spots of patches on the head or gills.

Sometimes, the lesions on your fish extend down to the sides, giving it the appearance of a saddle near the dorsal fin, and that’s why the common name for Columnaris disease is “saddleback disease”. Ultimately, as the bacterial infection progresses you may notice some other external changes in your fish such as moldy lesions around the mouth and frayed fins. Once the saddleback symptoms occur, a fish will usually survive 1-2 day days if left untreated until ultimately passing away.

However, not all symptoms are external. Some are behaviors that make your fish look more lethargic and weak, with a loss of appetite and hanging out at the surface of water.

What Are The Causes ?

The main culprit of the cotton wool disease or saddleback disease is a bacterial infection that particularly affects freshwater fish’s gills. Some of the major causes of columnaris disease in freshwater fish are:

1. Poor water quality

One of the main reasons your young fish might get Columnaris is poor water quality that compromises the overall health of your fish. 

High levels of ammonia, nitrates, and other pollutants can contaminate your entire tank water and induce stress in fish. Stress messes up the immune system of your fish, making them susceptible to fatal diseases like Columnaris. 

2. Stress 

As mentioned earlier, stress weakens the immunity system of your fish, making it more prone to diseases. Avoid overcrowding, choose suitable tank mates, and feed a balanced diet to eliminate stress in your aquarium. 

3. Injury

Fish with injuries in the form of wounds and lesions are more vulnerable to bacterial infections because Columnaris usually enter the fish through open wounds and lesions on the skin, gills, or fish’s mouth. 

4. Fluctuating water temperature

Studies suggest that fluctuating water temperature influences the metabolic rate of bacteria and affects their growth activity¹. Columnaris are mostly associated with warmer temperatures. Therefore, maintaining a stable water temperature for specific fish in your aquarium might help prevent Columnaris and bacterial proliferation. 

5. Untidy tank 

Columnaris bacteria thrive on uneaten food, fish waste, decaying plant matter, dead fish, waste products, and overall a contaminated tank with lots of pollutants. Therefore, it’s crucial to keep your tank clean with pristine water conditions for a healthy ecosystem. 

6. Poor nutrition

A balanced diet means a healthy immune system. A healthy immune system means a strong fight against bacterial and fungal infections. 

Feeding your fish a varied diet, rich in proteins and occasional treats is important to keep the livestock healthy and happy for a long period of time. 

7. Introducing New Livestock To The Tank

If you want to introduce a new fish into your tank, think again!

Because you never know what the fish might bring into your super healthy and playful aquarium. Quarantining a new fish into a separate tank is the most reasonable idea to avoid big problems such as Columnaris and other fish diseases. 

How Does It Enter Your Fish’s Body?

Columnaris strikes when the fish’s immune system is not strong enough to fight the bacteria. The bacteria can enter your fish’s body through gills, mouth, or small wounds on the skin. Therefore, the physical health of your fish is trivial to ensure the overall health. 

The cotton wool disease or saddle back disease is often spread through contaminated fish nets, containers, and uneaten food. Since the disease is highly contagious, it’s always recommended to sterilize your tank decorations or equipment to keep everything in prime condition. 

Conclusion

Columnaris disease is common in freshwater and tropical fish at water temperatures above 15°C or 59°F. At higher water temperatures, the progress of Columnaris disease is faster. Therefore, it is suggested to keep the water temperature low and stable throughout the year. Also, Columnaris bacteria love fish waste, dead fish, and organic waste. Therefore, proper filtration and weekly water changes should be done to prevent Columnaris in the long run. A good quarantine practice should prevent the problem entirely. 

Have any questions for me? Leave a comment in the comments below. I’m also leaving an FAQs section asked by some readers so you can review them as well. Thanks for reading and see you next time!

FAQS

How long can a fish survive with Columnaris?

The survival time of a fish with Columnaris depends on a number of factors. For instance, the severity of the infection, the presence of other stressors in your aquarium, and the overall health of your fish. The fish with the strongest immune system fight off the disease better than others. Therefore, it is important to understand the factors that may affect the lifespan of your fish in general. 

In some cases, Columnaris can cause instant death of your fish within a short period. It’s especially true if the infection is advanced and not treated properly. However, most cases of Columnaris can be treated successfully if diagnosed early with appropriate treatment. 

However, if your fish is already stressed or suffering from other health issues, it may have a hard time fighting off this disease. Therefore, it is important to monitor water quality and perform water changes regularly. Also, feed your fish a balanced, nutritious diet to support a healthy immune system. 

All in all, consult a professional before treating your fish or administering any special medicine for Columnaris.

Can fish survive Columnaris?

It depends on many factors such as the severity of the infection, the health of the fish, the effectiveness of the treatment provided, and if it is caught early.

Nonetheless, it is a highly contagious disease that requires swift intervention. Some of the factors that may help in the survival of your fish include:

1. Early detection by recognizing the symptoms of the diseases and starting the treatment promptly. The longer the infection progresses, the less chances of survival for your fish. 
2. Maintaining aquarium water quality and tank conditions by providing a stress-free environment is essential for the overall immune function of your fish.
3. Isolating the infected fish from the healthy ones can prevent the spread of the disease for more focused treatment 

Is columnaris a fungal or bacterial disease?

Many aquarists confuse Columnaris with a fungal infection. However, the causative agent of Columnaris disease is a bacteria named, Flavobacterium columnare, which is a gram negative bacteria affecting various freshwater fish. 

You can easily spot a fish with Columnaris disease by the presence of white, thread-like lesions on the skin, fins, and gills. And while Columnaris is a bacterial infection, it may give birth to many fungal infections.

Can salt cure columnaris?

Yes it can when done correctly. This blog post outlined a simple solution of using a hard dosage of salt to cure columnaris. It can be used to eliminate the disease as long as it is caught early.

How do you diagnose Columnaris disease?

Columnaris disease begins as external infections as lesions on the body surface and gills. However, the type of lesions depends on the fish. In catfish, some of the external symptoms are small and circular lesions with gray blue centers and red margins. However, in scaled fish, the lesions begin on the outer margins of the fins and gradually spread throughout their bodies. 

Some behavioral signs of Columnaris include lethargy, loss of appetite, erratic swimming patterns, scratching, and rubbing against the surface to aid discomfort. 

One of the obvious areas of examination is the fish’s gills. That’s because Columnaris directly affects the gills and may show signs of inflammation, discoloration, or excessive mucus production. 

Is Columnaris treatable?

As fatal and contagious as it may seem, Columnaris is definitely treatable with the right medications, early detection, and prompt intervention. 

How to treat columnaris in betta fish?

Treating Columnaris in betta fish is pretty much the same as treating any other fish. Use the same steps outlined in the post for betta fish. It should work the same with them. The main issue with bettas is the water temperatures, but Bettas can tolerate lower temperatures for longer than this treatment calls for.

How to disinfect aquarium equipment after each use?

While treating Columnaris outbreaks in your tropical fish tank, it is recommended to sterilize or disinfect all the tank decorations and other equipment after each use. For this, you can use the commercial treatment of Benzalkonium Chloride solution (Net Soak or Net Dip). Or you can also use hydrogen peroxide, and dip all of your tank decorations in 3% solution. 

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🐟 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.

Goldfish are surprisingly resilient, but they’re also prone to a specific set of health problems — many of which I’ve dealt with firsthand over 25+ years. The good news is that most goldfish diseases are treatable when caught early, and recognizing the symptoms fast makes all the difference. Here’s what to watch for.

Goldfish have a reputation for being nearly indestructible, but that reputation is largely undeserved — it’s more that goldfish tolerate abuse longer than most fish before showing symptoms. After 25 years in the hobby, I can tell you that the majority of goldfish disease cases I’ve seen trace back to the same root causes: overcrowding, inadequate filtration, and poor water quality. Fix those and most diseases never appear. But when they do show up, early identification is everything. Ich, bacterial infections, and flukes are all treatable if caught early — the same fish that recovers easily in week one often can’t be saved in week four when the infection has progressed. I’ve used everything from salt treatments to Prazi-Pro to API Furan-2 on sick goldfish, and I’ll share what actually works for each condition in this guide.

If you’re able to realize early on the signs and symptoms of disease and illness in your goldfish, then you can start treatment immediately and get your fish on the right track to living a long and healthy life. Otherwise, these sicknesses can be deadly.

The 14 Most Common Goldfish Diseases

Goldfish can contract the same diseases that most fish can in the aquarium hobby. For the most part, treatments for these coldwater fish are the same as they would be for tropical fish species.

In most cases, discoloration, lethargy, heavy breathing, and loss of appetite can be seen with any disease or ailment.

1. Ich

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One of the most common aquarium diseases of all time, ich, plagues goldfish aquarium setups. Ich, scientifically known as Ichthyophthirius multifiliis, is a parasite that affects the gills, skin, and fins of fish. Left untreated, this parasitic infection can quickly lead to death.

Symptoms

Luckily, fish owners have discovered numerous treatments for ich that result in full recovery. The best way to treat ich is through prevention and early detection. Here are some of the symptoms you should look out for when adding new fish to your aquarium:

• Flashing and scratching
• Small, dispersed white spots all over the body
• Heavy breathing
• Discoloration
• Lethargy
• Loss of appetite

The most recognizable symptom of ich is small white spots that cover the entire body, leading to ich also being referred to as white spot disease. These white spots appear as raised bumps over the gills, skin, and fins. They are about the size of a grain of salt and can appear in clusters or more randomly around the body in any amount.

Treatment

While white spots are one of the easiest symptoms of ich to diagnose, the parasite can live undetected in the aquarium for extended periods. In fact, these parasitic infections can be transferred between tanks through shared filter media, substrate, or other decorations. Because of this, the entire tank must be treated, not just the individual fish.

Some of the most popular treatments for ich include:

• Raising water temperature alongside frequent water changes
• New Life Spectrum Ick Shield
• Hikari Ich-X
• Seachem ParaGuard

What causes ich?

Parasites cause ich, however, other environmental conditions can determine the severity of the outbreak. Factors such as poor water conditions and the current stress on the fish’s immune system can increase the likelihood of the fish succumbing to the disease. As messy fish that create a lot of ammonia, goldfish are especially susceptible to stress and subsequent disease.

2. Dropsy

Dropsy is another common goldfish disease, but is, unfortunately, not easily treated. While dropsy is usually referred to as a disease, this condition is more like a symptom of a greater underlying problem.

Symptoms

Dropsy displays itself as:

• Swelling and bloating, especially in the eyes and abdomen
• Outward pointing scales
• Clamped fins
• Curved spine
• Discolored waste
• Discoloration
• Lethargy
• Loss of appetite

In addition to these symptoms, the fish may also show signs of other common goldfish diseases that may be the cause for the onset of dropsy.

Treatment

Treating dropsy is difficult and most cases are fatal. However, dropsy isn’t contagious, though the underlying bacterial, fungal, or parasitic infections may be. Because of this, it’s best to remove the sick goldfish from the aquarium and continue treatment in a quarantine tank system.

Here are some of the treatments you can try to alleviate dropsy symptoms:

• Frequent water changes
• Epsom/aquarium salt bath
• Seachem KanaPlex
• Seachem MetroPlex
• Fritz Aquatics Maracyn 2

I know both medications are not always available to some, so I’m going to defer to Lori’s Hartland’s experience on how she cured her Goldfish using a triple treatment of Kanaplex, Metroplex & Epsom Salt. Here is the full video below that walks you through her experience. It’s also very important to see her experience with her vet call at 19:06. She had to take a phone consultation, which is going to be what most will get when consulting a vet for a smaller fish.

What causes dropsy?

Dropsy is the secondary onset of symptoms caused by an underlying problem, usually a type of bacterial, fungal, or parasitic infection. The symptomatic swelling is caused by a dysfunction in the kidney or liver.

Because of the stress that the fish’s body is already under, antibiotics are only recommended if the underlying problem can be diagnosed as these medications heavily tax the liver.

3. Swim Bladder Disease

Another one of the most common goldfish diseases, swim bladder disease is challenging to treat but can be lived with. Like dropsy, swim bladder disease is often caused by an underlying problem, though it can be its own symptom.

Swim bladder disease, commonly referred to as swim bladder disorder, is a condition where the fish’s internal swim bladder organ dysfunctions. A healthy swim bladder allows the fish to regulate its orientation within the water column. A dysfunctioning swim bladder can cause the fish to swim upside down, on its side, or sideways.

Symptoms

Along with irregular swimming, the sick goldfish may show signs of:

• Swimming upside down or sideways
• Floating to the top of the tank or sinking to the bottom
• Distended abdomen
• Curved spine
• Discoloration
• Lethargy
• Loss of appetite

Treatment

Treatment for these buoyancy disorders is straightforward, but not always guaranteed to work. In some cases, the swim bladder is deformed for life. If this happens, goldfish owners become very innovative and perform surgery or provide a wheelchair for handicapped fish that are unable to regulate their orientation.

Here are some of the best ways to treat a sick fish dealing with swim bladder disorder:

• Fasting the goldfish
• Feeding peas and sinking foods that prevent the fish from gulping air
• Adjusting water parameters
• Wheelchair

The last method of treatment you won’t hear much of on many blogs. However, it is a great solution for fancy goldfish. This can be created with airline tubing. The video above from Mark Kennedy shows how to create a swim bladder wheelchair.

What causes swim bladder disorder?

Swim bladder problems can come about due to primary parasitic, fungal, or bacterial infections. Any one of the other common goldfish diseases can cause stress and damage to the swim bladder, resulting in too much gas being created or distributed incorrectly.

Otherwise, the actual disease can be caused by the fish gulping too much air at the top of the aquarium. Irregular digestion from a poor diet or incorrect water temperatures can also cause the swim bladder to create too much gas. Internal injury can also cause permanent damage to the organ.

4. Neurofibroma

One of the less common goldfish diseases to see in the aquarium hobby, neurofibroma is a condition where tumors grow from the nervous system¹. These tumors are often benign but can cause some discomfort as your goldfish tries to get around the aquarium.

In most cases, neurofibroma is no cause for concern. These tumors will often grow, fall off, and then regrow. While ugly to look at and sometimes uncomfortable for your goldfish, these tumors are usually not life-threatening.

Symptoms

There are not many symptoms of neurofibroma, but some things to look out for are:

• Discolored, raised bumps on the skin and fins
• Difficulty swimming

Treatment

While these benign tumors will usually manage themselves, surgical intervention is sometimes necessary. Veterinarians and fish specialists can biopsy the tumor and remove the affected cells. Therefore, the only successful treatment thus far has been:

• Surgical treatment and removal

What causes neurofibroma?

It is not fully understood what causes neurofibroma tumors to grow. While some cases may be due to environmental factors, the major key component is likely genetics.

5. Rot (Fin, Tail, Mouth)

Probably the second most common goldfish disease to see in the home aquarium is rot. Rot can affect the fins, tails, and mouths of fish and lead to death in severe cases. Luckily, fin rot is very treatable and highly preventable.

There are two main types of rot, one caused by bacterial infections and the other by fungal infections. Sometimes, these can both happen at the same time and share many of the same symptoms.

Symptoms

Here are some of the most common symptoms to see alongside bacterial and fungal rot:

• Clamped fins
• Discolored and irritated fins and skin
• Frail and fraying fins
• Open sores
• White, cottony growth for fungal diseases
• Discoloration
• Lethargy
• Loss of appetite

Treatment

Treatment for these bacterial and fungal infections is easy and straightforward. Rot is not necessarily a problem within itself, but is often the result of poor water quality. However, most fishkeepers treat the symptoms alongside the cause.

Here are some reliable treatments for infected fish:

• Frequent water changes
• Aquarium salt bath
• Fritz Aquatics Maracyn 2
• Seachem PolyGuard
• API MelaFix

What causes rot?

Simply put, rot is the result of goldfish living in poor water quality. Thousands of microorganisms live in our aquariums, some good and some bad. If the goldfish’s immune system is compromised or is physically injured, these microbes can enter the fish’s system, leading to fin rot or infection in other areas of the body.

6. Fungal Infections

The most common fungal infections arise from fin rot. Instead of bacteria infecting the open wounds or compromised sites of the fish, fungus, often from the Saprolegnia and Ichthyophonus genera, takes root and eats away at the fish. Cotton wool disease should not be confused with a fungal infection as those symptoms are caused by bacteria, namely Flavobacterium columnare.

Symptoms

It should be noted that a fungal infection does not necessarily indicate fin rot. Here are some of the symptoms that might appear on a fish’s body that’s struggling with fungus:

• Cotton-like growth on the fins and body
• Discolored grey or white patches
• Ulcers and cysts
• Discoloration
• Lethargy
• Loss of appetite

Treatment

Luckily, many medications target fungal diseases. Still, the best way to prevent and treat these outbreaks is by keeping aquarium water stable and clean. Here are some of the best goldfish fungal treatments available:

• Frequent water changes
• Aquarium salt
• Fritz Aquatics Maracyn 2
• API PrimaFix

What causes fungal infections?

Like a bacterial infection, fungal infections are caused by what’s already present in the aquarium. A goldfish tank is filled with good and bad organisms that will take advantage of a sick fish. However, some fungi are only able to thrive when dead and decaying matter is available. Once the dead fish, plant, or invertebrate has been removed and water quality improves, then the fish should start to get better.

7. Velvet

Velvet is a very aggressive disease and quickly causes sudden death for goldfish. This is another parasitic infection caused by dinoflagellate species in the Oodinium genus.

Like ich, these tiny parasite species live in the environment until they’re ready to attach to a fish. Once mature, they inject themselves into the fish’s slime coat. This infection eventually causes the gills and internal organs to inflame, leading to serious tissue damage.

Symptoms

Velvet is also commonly known as rust or gold dust disease due to its appearance on the fish’s skin. Here are the other ways you can diagnose velvet:

• Fine white or rust-colored specks/coating that cover the body of the goldfish
• Flashing and scratching against aquarium objects
• Clamped fins
• Abrasions and lesions
• Heavy and rapid breathing
• Discoloration
• Lethargy
• Loss of appetite

Treatment

Velvet is very difficult to treat because it progresses so quickly. If it’s caught early, then you may be able to save your goldfish. One of the best prescribed methods of beating velvet is by blacking out the tank by not allowing any light to enter as dinoflagellates are photosynthetic. Here are a few other ways you may help your fish:

• Raise the water temperature
• Create black-out conditions
• Seachem ParaGuard
• Seachem Cupramine

What causes velvet?

Velvet is a nasty parasitic infection that is similar to ich but more challenging to treat. This is caused by a photosynthetic dinoflagellate that has three life stages, including one that lives in the substrate, a free-swimming form, and one that requires a host in the form of a fish.

Because of this, velvet can easily be transmitted through sick goldfish or the transfer of aquarium media. The best way to prevent velvet is by observing new fish and using a quarantine tank.

8. Flukes

Flukes are very common among goldfish, especially fish that live in outdoor settings. Flukes, also known as trematodes, are types of external or internal parasites that can affect any part of the body. One of the most common flukes to diagnose is gill flukes, which are more difficult to treat.

Symptoms

Internal parasites can be more difficult to diagnose than external ones, but here are some of the warning signs:

• Redness and inflammation
• Flashing and scratching
• Excess mucus secretion
• Heavy breathing
• Discoloration
• Lethargy
• Loss of appetite

Treatment

Goldfish suffering from flukes have a relatively high chance of survival as long as treatment is started immediately. Luckily, most of the aquarium treatments available are very effective, and it’s usually not necessary to use more than one method.

• Aquarium salt
• Seachem Paraguard
• Hikari PraziPro

What causes flukes?

Flukes are parasites that are often carried into a tank on other fish and invertebrates. While they’re common to see in the aquarium setting, they thrive in outdoor environments. This is because most flukes require one or two more additional hosts, including birds and snails. This makes transfer from one outdoor system to the next relatively easy.

9. Anchor Worms

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One of the easiest goldfish diseases to diagnose, anchor worms can be scary to see on your fish. These are a type of crustacean parasite that belongs to the Lernaea genus. Luckily, they are macroscopic external parasites that can easily be seen and diagnosed by the naked eye.

Symptoms

Here are some ways to tell if your fish has an anchor worm infection or not:

• Thin white thread-like worms (sometimes Y-shaped) attached to the fish’s skin
• Redness and inflammation
• Lesions and abrasions
• Flashing and scratching
• Discoloration
• Lethargy
• Loss of appetite

Treatment

Treatment for anchor worms can take some trial and error. The best method is to move the affected fish to a quarantine tank, allowing the main goldfish tank to run empty, administering medications, and giving mild salt bath treatments. Here are some of the recommended treatments:

• Aquarium salt
• Fritz Aquatics Mardel Clout
• Seachem Paraguard
• Seachem Cupramine

What causes anchor worms?

Like other parasites, anchor worms can enter the aquarium via new fish or used plants and decorations. These parasites undergo several life stages, some of which are free-swimming, making transferral through different media very easy.

10. Ulcers

Ulcers are a big problem for the koi and goldfish industry but are often a sign of a bigger underlying problem. While not usually deadly on their own, ulcers can fester and become a breeding ground for bacterial and fungal infections.

Although ulcers aren’t contagious on their own, most fish exposed to those conditions suffer in one way or another due to environmental factors or secondary infections. The video by ThinFrog above highlights the aliment and how to cure it.

Symptoms

Here are some of the symptoms that might accompany ulcers:

• Redness and inflammation
• Open sores and lesions sometimes expose the muscle tissue
• Cloudy and bulging eyes
• Discoloration
• Lethargy
• Loss of appetite

Treatment

The first step to treating ulcers is finding the underlying problem. Most often, these abrasions come about due to poor water parameters, injury, or other stressors. It is key to treat those problems first, while also providing care to the wounds and preventing further infection from developing.

You can treat ulcers with:

• Frequent water changes
• Aquarium salt
• API MelaFix
• Fritz Aquatics Maracyn 2

What causes ulcers?

Ulcers can be caused by any one of the common goldfish diseases on this list. They are often the result of poor water quality, but they can be caused by a previous injury that hasn’t healed properly. Ulcers are often worsened by secondary infections and other goldfish parasites.

11. Carp Pox

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One of the less common goldfish diseases, carp pox is mainly seen in koi. This disease is caused by the herpesvirus, also known as the Cyprinid herpesvirus 1 (CyHV-1). As a herpesvirus, symptoms can lay dormant until a certain stressor arises.

Symptoms

Many hobbyists are unfamiliar with carp pox and you might not even know your goldfish is a carrier, so it’s important to be able to identify these symptoms:

• Moderately sized milky bumps and lesions on the skin
• Bumps around the mouth region
• Thickened skin around the fish’s fins

The good news is that carp pox is very survivable as long as a secondary infection doesn’t develop. At the same time, it’s safe to assume that all fish housed with a carrier of carp pox have been exposed to the virus.

Treatment

Unfortunately, there is no treatment for Cyprinid herpesvirus 1 (CyHV-1) and the fish will have the virus for the duration of its life. Raising the water temperature and keeping water parameters good can help bolster your goldfish’s immunity and help deter outbreaks.

What causes carp pox?

Carp pox is caused by Cyprinid herpesvirus 1 (CyHV-1). Fish become infected when the virus sheds off the skin of the infected fish into the water column and the system of another fish.

12. Cloud Eye

Cloudy eyes are rarely a standalone symptom and often indicate a bigger problem at hand. While a cloudy eye may be the result of an injury to the eye, it’s much more likely that the fish is suffering from an underlying infection.

Symptoms

Along with a cloudy eye, your fish may experience:

• Cloudy or opaque eye
• Bulging or swollen eye
• Difficulty swimming and navigating
• Blindness
• Discoloration
• Lethargy
• Loss of appetite

Treatment

A cloudy eye should be treated immediately to prevent the goldfish from losing its eyesight. At the same time, the underlying problem should be treated as well. This might include poor water quality or other internal infections.

Some treatments for cloudy eyes include:

• Frequent water changes
• Removing sharp objects
• Aquarium salt
• API MelaFix
• Seachem KanaPlex

What causes a cloudy eye?

Cloudy eye is the result of some of the most common goldfish diseases, like the ones already on this list. Primary infections can cause the fish’s eye to swell and discolor as a result. However, a cloudy eye can also be due to an injury, so it’s important to get the correct diagnosis to proceed with the right course of treatment.

13. Pop Eye

Pop eye usually goes alongside cloudy eye (betta fish shown as I couldn’t find one of a goldfish). Again, this symptom is usually the result of an underlying problem, like an infection, though it can also be due to injury. The difference between pop eye and cloudy eye is that one or both eyes bulge out from the socket. The eyes don’t necessarily need to be discolored but often are.

Symptoms

Here are the main symptoms of pop eye:

• Bulging eye or eyes
• Disfigured eye socket
• Cloudy or filmy eyes
• Difficulty swimming and navigating
• Blindness
• Discoloration
• Lethargy
• Loss of appetite

Treatment

The treatments for pop eyes are usually the same as for cloudy eyes. It’s important to deter further infection from developing and to figure out the problem at its core. Here are some of the recommended treatments for pop eye:

• Frequent water changes
• Removing sharp objects
• Aquarium salt
• API MelaFix
• Seachem KanaPlex

What causes pop eye?

Pop eye is most often the result of poor water quality or injury to the eye. Bulging eyes can also come about due to a primary infection, like a parasitic or bacterial infection. Pop eye is often accompanied by cloudy eyes.

14. Bacterial Infections

Our aquariums are filled with bacteria, some good and some bad. If a goldfish is compromised due to stress, injury, or other disease, then bacterial infections will take hold. You can see an example of a bacterial infection from the video by Aquafish Groomer above.

There are many different types of bacterial infections, and some can cause secondary symptoms that will also need to be addressed. It should be noted that a bacterial infection can develop due to one or more of the goldfish diseases on this list.

Symptoms

Here are some of the most common symptoms of bacterial infections seen in goldfish:

• Clamped or frayed fins
• Difficulty swimming
• Redness and inflammation
• Discolored or swollen eyes
• Abnormal feces
• Discoloration
• Lethargy
• Loss of appetite

Treatment

With careful attention, most hobbyists can narrow down the bacterial infection they’re dealing with so that they can use a specific medication. In some cases, it may be necessary to use a general antibiotic. Some of those include:

• API E.M. Erythromycin
• API MelaFix
• Seachem KanaPlex
• Fritz MetroCleanse

What causes bacterial infections?

There are many reasons why a bacterial infection might develop in a fish tank. The main reason is due to a compromised immune system, either due to stress, injury, or another disease.

General bacterial infections can be difficult to treat and it’s best to narrow down the specific type of bacteria you’re dealing with as best as possible. For the most part, though, bacterial infections are not contagious by themselves.

15. Constipation

Constipation is embarrassing but is one of the most common goldfish diseases to treat. Luckily, constipation is pretty easy to treat as long as you give some extra care and attention to your fish.

Symptoms

It might be difficult to tell if your fish is constipated, especially if it’s still asking for food. More food will only cause more damage, so keep a lookout for the following symptoms:

• Less frequent waste production
• Discolored feces
• Abdominal bloating/swelling
• Buoyancy disorders
• Lethargy
• Loss of appetite

Treatment

Once you’ve realized that your fish is having difficulty passing waste, treatment is relatively straightforward. Luckily, constipation doesn’t usually require medication treatment.

Here are some ways to relieve your fish:

• Epsom salt bath
• Fasting
• Feeding peas
• Dietary adjustments
• Increase water temperature

What causes constipation?

Like other animals, goldfish constipation is largely due to improper digestion. This can be the result of a poor diet that doesn’t meet dietary needs or overfeeding. It can also be due to digestion tract dysfunction, which could be indicative of unfavorable environmental conditions.

FAQs

Final Thoughts

Goldfish are hardy fish but are susceptible to aquarium diseases just like any other domesticated species. Some might say goldfish are especially likely to contract deadly illnesses due to the poor conditions and water quality they’re usually kept in. It’s important to be able to identify the symptoms of some of the most common diseases and have medications on hand when and if the time comes.

Otherwise, make sure to quarantine all new fish and invertebrates to guarantee the most success.

Fin rot is one of the most common health issues I see in bettas, and also one of the most commonly misdiagnosed — people often confuse it with mechanical fin damage or fin biting. After keeping bettas for over 25 years, I know exactly what to look for and how to tell the difference so you treat the right problem.

Fin rot and mechanical fin loss look similar but require completely different responses — and treating the wrong one wastes time and can actually stress your fish further. Here’s how I tell them apart after keeping bettas for years: fin rot has a ragged, uneven edge that often shows darkening or discoloration, and it progresses over days if untreated. Mechanical damage from sharp decorations or fin-nipping tank mates tends to have a cleaner tear line with no discoloration, and it doesn’t spread. Fin rot needs treatment — I reach for clean water first, then Kanaplex or API Furan-2 for bacterial cases. Mechanical damage just needs the cause removed; the fins grow back on their own given good water quality. Getting this diagnosis right is step one, and that’s what this article is about.

Betta Fin Rot Vs Fin Loss – What’s The Difference

Betta fish can suffer from a condition called fin rot, which is caused by either bacterial or fungal infection. Symptoms should be identified as soon as possible to ensure the betta’s recovery. If left untreated, it could lead to deadly complications. Treating and curing this illness in time is key for its successful management. Fin loss occurs due to injury.

Symptoms

When it comes to fin rot, monitoring your betta fish is important as the symptoms may be hard to spot at first. Signs of this condition can include dark or bloody fins, unusual edges on their fins, lethargy, and white spots appearing on the tips and frayed/ragged edges. As time goes by, these issues worsen with shredded flaps along the exterior as well as possible development of sores that look bloodied up while also noticing a marked decrease in length from when they were healthy before.

The symptoms will often go in stages:

• Stage 1 – Discoloration on edges of fins
• Stage 2 – Ragged fin edges
• Stage 3 – Missing fins or tails

If your fish reaches stage 3, there is a high probability of loss of life. Other symptoms include sluggish behavior and lack of appetite.

Causes

Properly managing water temperature and routinely monitoring tank water parameters are key steps to prevent fin rot from developing in betta fish. These factors, such as elevated ammonia levels or pH fluctuations, can be highly toxic and induce stress which makes the fish more prone to this infection. Poor quality of water is also one of the main causes. When these conditions deteriorate, it increases their susceptibility even further.

Identifying Fin Loss

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Betta fish may be subject to physical injury resulting in fin loss due to sharp tank decorations and aggressive tank mates, as well as rough handling. For more serious complications to be prevented, the symptoms of such an issue should be ascertained and its causes identified since it is distinct from fin rot.

Symptoms

It is vital to keep an eye out for any red flags of trouble in your betta fish, especially if their fin loss shows up suddenly. Fin loss is injury related and could become infected. Look around for environment factors that causing the problem.

Causes

In order to stop fin loss in betta fish, it is essential to identify and address the underlying causes. Some of these are sharp tank decorations, aggressive tank mates that exhibit bullying behavior such as chasing or attacking them, and careless handling of the fish itself which can result in physical damage or stress induced fin loss.

The betta fish itself could also be the cause. Some betta fish when bored or stress will bit their own fins and this may cause fin loss or fin rot. The other factor is too much interaction with their reflection, which ends up getting them injured when they try to fight themselves.

Prevention

To decrease the chance of betta fish fin loss, careful monitoring and well chosen tank decorations are key. For decor, look for items that are smooth and if you get fake plants, purchase the silk kind as they will not get caught on your Betta’s fins. Gravel should be smooth, with fine gravel or sand being the most preferable.

Fin loss can be more concerning initially than fin rot because if the injury is severe, the fin may not grow back fully or can get infected. Treat a fin loss injury as stage 3 symptom like you would with fin loss. While they can go back on their own, infection could sink it and monitoring should occur. The good thing with fin loss vs fin rot is that oftentimes times, the fish will still actively eat with the injury.

Treating Rot

Assessing the seriousness of fin rot is essential when determining how best to treat it, as this will ultimately affect your betta’s chances at a full recovery. To address the infection accordingly, different approaches may be necessary depending on its severity.

The first thing to look at are your water parameters. Fin rot is usually caused by poor parameters. Take our your test kit and look for 0 ammonia, 0 nitrites, and under 40 PPM nitrate. You may need to do water changes, feed less, or reduce livestock to get levels where they need to be. Live plants are a great long-term fix but address the immediate issue first before getting into plants.

Mild Cases

When it comes to treating mild fin rot in betta fish, water quality must be improved and monitored. Cleaning the tank is also essential. Regularly performing water changes should be done daily or every other day so as to keep clean waters which can help both remove any toxins that may contribute to fins deteriorating, while promoting healing at the same time.

Also, look at your water flow. If your flow is too strong for your betta this could cause fin rot to occur. Look for sharp decor that may cause injuries. Lastly, check your temperature and see if it is correct. 78 to 80 degrees F is best for them.

If improvements are seen with this disease, then there will no longer be black edges on their fins. A whitish/clear membrane along its edge could form. Similarly, if white areas around those frayed ends have faded away or disappeared all together, these signs point toward recovery from a mild case of fin rot taking place over two up to six weeks duration for full restoration back into healthfulness again!

Severe Cases

In the event of a serious betta fin rot occurrence, it is essential to keep track of water quality and separate the fish in order for medication to be administered appropriately. The first step is to clean out your fish tank to get your nutrient levels in check, as many medications you will use will recommend that you not do water changes during treatment.

Consulting with veterinary or other hobbyist experts before using any antibiotics (i.e., erythromycin) should also be done when treating severe fin rot situations. Treatment should be effective quickly as a fish with fin rot can be afflicted with a secondary infection (due to a weakened immune system) that will often take the fish’s life. A broad spectrum antibiotic is my recommendation when you need to get serious. Erythromycin is a good solution for rot and should be done in a hospital tank. With a hospital tank, you can double up with a product like Ich-X to protect against parasitic infections. Do not use these medications in a planted tank or with inverts as it will damage or kill them.

Make sure you remove any chemical filtration when treating your tank, as they will absorb it. Medication will need to stay in your tank for at least a week without a water change so the antibiotics can do its job. Antibiotics have a tendency to reduce oxygen levels so consider adding an air stone or sponge filter to increase your levels.

Addressing Fin Loss

To successfully treat fin loss in betta fish, a clean and healthy environment is essential. This will aid the healing process as well as reduce any risk of infection.

Treatment

In order to deal with fin loss, a number of steps can be taken. Firstly, it is important that the tank holds clean water as this will aid in betta fish recovery from their fin loss. It’s also essential to use slime coat booster so healthy fins regrowth can occur for your betta fish and ensure any sharp objects or aggressive aquatic life are removed that may cause injury when combatted with weakened fins due to lost ones already present on the creature itself.

Stress coat products along with aquarium salt should also be considered treatments for improving an afflicted fish’s condition while at the same time remembering safety must come first by covering filter intakes with sponges, which could potentially harm their vulnerable fins even more than before initiated help was given forthwith afterwards.

Recovery

The regrowth of betta fish fins post fin loss can take anywhere from a few weeks to months, depending on the seriousness of the injury. Signs pointing towards successful recuperation may consist of renewed fins, healthy edges being restored, and with color vibrancy appearing again. Also, increased energy levels and activity plus no black streaks or discoloration seen on the betta fish’s fins would be good indications, too.

It’s also normal for your Betta’s regenerated fins to be a different color than they originally were as they grow back.

Preventing Future Issues

Ensuring a healthy habitat for betta fish is the best way to stop any kind of fin problems, including rot and loss. To create an ideal environment, carefully consider your tank setup as well as water quality in order to make sure that you have a beautiful and strong betta fish living with you for years on end.

Water Quality

It is important to ensure good water quality in order to prevent potential health problems for betta fish. To be proactive, performing a 25% water change weekly can help maintain the health of your aquatic companion. It’s also essential to keep an eye on and adjust any necessary parameters such as temperature (in between 78-80°F or 25-26°C), pH level, ammonia, nitrite levels, and nitrate concentrations. All ideally towards neutral conditions around 7pH.

Tank Setup

When designing a fish tank for betta fish, it’s important to select appropriate tankmates that are non-aggressive and provide plenty of smooth decorations which can minimize the risk of injury or stress. Live plants are optimal in a betta fish aquarium as they help boost water quality while giving them extra nutrients with natural decor such as driftwood, moss balls, and leaves designed specifically for these species. It is best to avoid aggressive inhabitants like angelfish, barbs and fin nipping tetra species since these fish can harm your Betta.

Choose Shoter Finned Varieties

Bettas with shorter fins are less prone to rot or fin loss. They can swim stronger, tolerate strong water flows, and are injured less by decor. If you want to lessen your chances naturally, consider purchasing a Plakat betta variety, as they tend to be more hardy, active, and less prone to injury or infection.

Frequently Asked Questions

Closing Thoughts

With all the fancy finned varieties of Bettas available now and with new breeds being introduced, running into fin rot in Bettas is becoming more common. If you set up the right environment, keep healthy parameters, and choose the right tankmates, you should be able to prevent rot or loss from happening.

What’s been your experience with either condition? Let us know in the comments and let’s start a conversation. It’s always great to hear from other betta pet owners.