Guppy Grass – A Great Plant For Breeding Fish

Guppy grass is a really popular plant in the planted tank hobby, and for good reason. This plant is very easy to grow and has plenty of great benefits for your livestock.

Guppy grass can be a difficult plant to keep under control in a small tank though and tends to take over pretty fast. It is also a great plant for breeding fish, as young fish will feed on the guppy grass and will give them the much need shelter they need to grow (which one of many benefits of guppy grass). Read on to learn everything you need to know to successfully grow and care for this undemanding and fast-growing aquatic plant in your aquarium.

A Brief Overview Of Guppy Grass

Scientific NameNajas indica (other less common species is guppy grass najas guadalupensis)
Common Nameswater nymph, najas grass, guppy grass
OriginTropical from India to Japan
Skill LevelEasy
LightingLow, 35-50 PAR (Umols)
Tank PlacementMidground, Background, Floating
Flow RateLow
Temperature Range71 – 86 F
Height4 – 12 inches
pH Range6-7.5
PropagationShoot cuttings
Growth RateFast
Feed TypeColumn Feeder
CO2 RequirementNo

Origins And Habitat

Guppy grass, Najas indica, grows in a variety of slow-moving to still freshwater and brackish environments. This aquarium plant is most common in shallow water but can be found down to about 15 feet.

They occur naturally in Tropical Asia, occurring from India, through China to as far east as Japan, and south to New Guinea. Guppy grass species have also been introduced to countries outside of their native ranges where they have become invasive.

Remember to never dispose of guppy grass or any other aquarium plant or trimmings in local waterways, even if the plant is native to your country.

What Does They Look Like?

How Does Guppy Grass Look Like

Guppy grass (picture source) is a light to dark green stem plant. They are slender, fully aquatic plants. Their stems reach a length of 20 inches and are heavily branched with fine shoots. The lower nodes often have a weakly developed, white root system.

Guppy grass plants are covered in very fine needle-like leaves of about an inch in length. The leaves are whorled around the stem and show some variation depending on whether the plant is grown rooted or kept as a floating plant.

Placement And Lighting

Guppy grass (also known as water nymph) is not really a plant for intricate, finely planned aquascapes because it is fast-growing and occupies the water column in the aquarium. It can quickly shade out other plants grown below it.

This is an ideal plant for aquarists who keep small fish and shrimps that prefer good cover to feed, hide, and spawn/breed in. This makes guppy grass a very useful freshwater plant for fish breeders.

It can be grown quite easily in bare tank environments and it creates a natural but easy to maintain environment for growing out fry. These plants can also be rooted and grown as a background plant or in the midground of your tank.

They are column feeders so by rooting them in the substrate you are really just controlling their position in the tank, helping you keep the aquascape more organized. Take care when you plant guppy grass since they are very brittle and can break easily.

An easier way to keep them in a specific position in the aquascape is to weigh the plants down to the substrate. You can do this with rocks or use specially designed aquarium plant weights. Alternatively, you can simply allow these plants to float in low-flow aquariums.

Najas grass doesn’t need powerful planted tank lights and will grow low-light conditions. Higher, for the best growth, aim for moderate light for deep green specimens that grow dense and healthy.

What Are Good Tank Mates?

Guppy grass can be kept with most tropical freshwater fish and dwarf shrimp. It is great for soaking up extra nutrients in more heavily stocked aquariums.

It provides the perfect structure for fry and small livestock to shelter in and the plant also has a huge surface area for biofilm and micro-organisms to grow on. Apart from providing food and shelter, guppy grass also produces a lot of oxygen in the water column which is great for your livestock.

Good Tank Mates

Guppies and other livebearers like mollies are classic tankmates for this plant because they spawn within the stems and shoots and their fry find safety there. Egg-laying fish and shrimp will also use these plants for breeding and baby fish are able to use guppy grass as hiding places from larger fish.

This is a versatile species, however, and many small fish and shrimp species will enjoy the environment it creates. Plant-eating fish like goldfish will happily feed on this soft species, and being such a fast grower, they can often keep up with the fish’s appetite if kept in very lightly stocked tanks.

Fish Species To Avoid

The plant itself is safe to keep with just about any kind of small shrimp or aquarium fish. If you don’t stay on top of trimming it, however, it can really crowd out an aquarium. That is something you want to avoid if you keep active species like zebra danios that enjoy plenty of swimming space.

If you don’t want fish to feed on your guppy grass, avoid keeping cichlids, silver dollars, and goldfish because they will happily eat this species.

Feeding and Fertilization

Guppy grass usually doesn’t need to be fed, especially if kept in aquariums with fish and other livestock. The waste produced by livestock and the nutrients in any uneaten fish food will often be all that is needed.

To improve growth in very low nutrient setups or keep up with the demand from plant-eating livestock in your tank, you can dose guppy grass with a balanced liquid plant food.

How Much And How Often To Feed

With fast growing guppy grass, less is usually more. Since guppy grass does best when grown under only moderate strength lighting and since a CO2 system is not necessary, heavy feeding is not recommended. A light application after your regular water changes should be all that is needed.

Different Types

Najas guadalupensis

There is another popular and widely available species of guppy grass known as Najas guadalupensis that has a faster growth rate. This species is native to the Americas, growing from Canada and the United States to South America in regions like Argentina.

This guppy grass is very similar in appearance to N. indica, although it this variety of guppy grass grows a lot taller, reaching around 3 feet, and usually has slightly shorterleaves.


Guppy grass is very easy to care for and is a great species for beginners. If anything, this aquatic plant tends to be too easy to grow.

Guppy grass care is mostly about keeping the plant trimmed and can keep the aquarist pretty busy, especially in smaller tanks.

Planted Tank Parameters

Guppy grass is a very hardy and adaptable species that can survive in temperatures between 71 and 86°F. pH values around neutral are best, but anywhere between about 6 and 7.5 are suitable for the water nymph. Because it can survive higher temperatures, it is a good candidate of Discus and Brackish water setups. Given their higher temperature requirements an aquarium heater is a good consideration.

CO2 injection is not necessary to grow healthy guppy grass but if you do plan on running carbon dioxide in your tank, keep your levels below 30 ppm. Another important tip is to time your injection to start 2 hours before the start of your lighting period. A Water hardness between 5 and 20 GH and a tank size of 10 gallons or more is recommended.

Water Quality

Guppy grass is not very sensitive to conditions but you should aim to maintain good water quality and stable parameters for the sake of your livestock and any more sensitive plants you keep.

One of the great benefits of guppy grass is its ability to soak up excess nutrients in the water column, helping to maintain and even improve conditions. By keeping nutrient levels in check, guppy grass also helps to keep algae under control.


Guppy grass has no specific filtration needs. They actually assist in aquarium filtration because they are hardy aquatic plants that feed from the water column, taking up excess nutrients and metals in the water.

One important thing to mention in relation to filtration is this plant’s tendency to break apart in strong currents. The fine leaves and shoots can easily block up your filter media so use a sponge filter or a filter with a prefilter sponge on its intake to prevent this.


Guppy grass will survive in aquariums with a strong flow but because they are pretty delicate, you’re going to pick up some problems with shoots and leaves breaking off and floating up to the surface of your tank.

A much better idea is to grow this plant in aquariums with a slow, gentle flow like they are adapted for in nature.

Aquarium Maintenance

Testing Water Conditions

Being able to test your own water conditions is very important for aquarists and will save you a lot of headaches when caring for and growing different plants and animals in your tanks. Liquid test kits simple strip tests are available at your local fishkeeping store or online.  

Guppy grass is not a very sensitive species, but nevertheless, you should test your aquarium water before adding a new plant to find out whether your water parameters are in line with the plant’s needs. The most important parameters to test are water hardness, ammonia, nitrites, and pH.

Guppy grass is very useful for keeping water parameters stable in the planted tank, but go ahead and retest the water before and after a water change to see how much your values are fluctuating, the information could be critical for more sensitive species in your aquarium.

How To Set Up Your Aquarium Tank

Guppy grass doesn’t have any special tank requirements outside of what you would normally find in a tropical freshwater aquarium. Being a column feeding plant, your choice of substrate is pretty irrelevant and these plants will do fine in inert gravel substrate.

You might find that the below-ground part of plants rooted in a very fine aquarium substrate will cause guppy grass melting due to lack of flow, in which case simply anchoring the plants with a plant weight is a better idea.  

Guppy grass can be kept in any size tank but it’s best suited for tanks over 10 gallons because it can choke up a nano tank pretty fast if not trimmed regularly.

How To Propagate

Najas grass couldn’t be much easier to propagate. Simply cut, or tear off a part of the parent plant and float it in your tank. The shoots that tend to break off easily will usually continue to grow into full-size plants so these water nymphs propagate themselves a lot of the time.

Aquarists should always take special precautions when disposing of guppy grass trimmings. rapid growth species like Najas indica can cause all sorts of problems if they get into wetlands and other ecosystems where they don’t belong1.

Health And Disease

Signs Of Health

Healthy guppy grass will be green, with fine white roots, and have many branches covered in healthy leaves. They are naturally fragile stem plants so don’t be too concerned if a few shoots and leaves break off, often they can be turned into new plants.

Signs Of Ill Health

 There are a few tips you want to keep in mind when buying najas grass. Plants that have turned yellow or brown are not in good health and should be avoided.

Water nymphs that have shed their leaves might be in ill health or have just taken mechanical damage during handling or transport and could recover quickly. Najas grass with a red color has been grown under lights that are too strong and been burned.

Najas grass is a rapid growth and hardy plant though, so don’t be too quick to discard a specimen. Usually, these plants will bounce back quickly if given the chance in the right parameters.

Common Health Issues And Treatment

Melting is one of the most common problems with many aquarium plants, especially when they are put into a new tank. Unfortunately, this can happen with guppy grass as well.

Stay on top of removing dead and detached plant parts from your tank to prevent them from fouling your water until they have recovered. A fine mesh aquarium net works well for this job.

Plant Pests

Dragonfly (nymph)

If you don’t want to risk setting snails and other unwanted organisms loose in your tank with a new plant, a bleach dip is a good option. Najas grass is not often available as a tissue culture, so this is usually your best bet.

These are soft and delicate plants so you need to be careful not to damage them, either physically, or from overexposing them to bleach during the process.

Use a mixture of just 1 part bleach to 20 parts water for your dip and keep the plants in contact with the dip for not more than a minute. After dipping, you’re going to need to rinse them off properly because the bleach will continue to work.

Prepare a bucket or something similar with clean water with an added conditioner and have this ready before you dip your plants in the bleach solution. Work quickly when bleaching these plants but remember how soft and fragile they are too.

After rinsing in freshwater with added conditioner, you can rinse them some more in freshwater to be extra safe, or proceed to add them to your aquarium. Making the decision to quarantine guppy grass is a wise choice if purchased locally. Due to the cheap price, it is often not keep in pest free environments.

Where To Buy

Najas grass is pretty easy to find at most pet stores and fish-keeping stores. It grows really fast and so most keepers will be able to give you a couple of trimmings from their plants too. The main thing you will find in stores and online will be the Najas guadalupensis species. The Najas incida species is harder to find.

Guppy Grass (Najas indica)

Guppy Grass is a great plant for breeders and beginners. It is stress free, grows fast, and helps remove nutrients in an aquarium

Click For Best Price

However, one such online store that sells them would be BucePlant. You can get quality plants from them. They have an amazing selection!


Does How fast does they grow?

Guppy grass is one of the fastest-growing stem plants in the hobby. Actual growing speeds will vary depending on nutrient content, parameters, and lighting conditions but these plants are well known for filling up small tanks in just weeks.

What is it good for?

Guppy grass is especially good for fish and shrimp breeders looking for a fast-growing species that provides shelter, increased oxygen levels, and habitat for newly hatched fry and baby shrimp larvae.

As fast-growing stem plants, guppy grass also controls algae growth in the aquarium. For aquarists who like a dense, fully green aquascape, this najas grass is ideal.

Do guppies like this?

Guppies are great fish to keep with najas grass, but there are many other excellent tank mates as well. Guppy grass gets its name because it creates the perfect habitat and hiding spots for guppy fry.

Does they need to be planted?

Guppy grass grows best when allowed to float in the aquarium although it can be planted in the substrate as well. It is a column feeder with weak roots, so plant weights are also useful to keep the plants anchored in one part of the tank.

Closing Thoughts

 If you’re looking for an easy, fast-growing stem plant for the planted tank that doesn’t need much in the way of lighting, hardware, and fertilizers, guppy grass will fit the bill. These plants are perfect for fish and shrimp breeders looking to create a safe environment for their fry to live and grow.

Just bear in mind that, in the right environment, najas grass grows at a serious rate and can fill up a tank and crowd out other plants in no time.

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