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Guppy Grass

Posted by Henry Yang on

Guppy Grass


Guppy grass is also called najas grass and Common water nymph. Scientifically named Najas guadalupensis is a quick-growing plant that produces oxygen by consuming all of the nutrients in the tank. It is famous among aquarists for its use in guppy tanks. It belongs to the genus Najas also called water nymph in the family Hydrocharitaceae

Origin and Habitat

It is indigenous to North America and can also be found in Central America, South America, Canada, the Caribbean, Mexico, and lastly, Asia. In the wild, it is mostly found near water bodies like ponds, flowing streams, brackish lakes, and freshwater sites. In few countries, guppy grass is considered an invasive species because of its growth in local canals and waterways.


It grows underwater, has long slender stems with many branches. It can grow to 90 cm in height which is 35 inches. Its leaves are delicate, green, flexible oppositely arranged in whorls, and contain teeth on the edges. The leaves are up to 2 cm wide and 3cm long.

Reasons to have this in your tank

It removes toxins, heavy metals, nitrite, nitrates, and ammonia from tank water and produces oxygen. Thus eliminating a chance of algal growth in the aquarium. 


As its name says it is great for having guppies. The plant has lots of cavities where shrimp hang out to search for food or simply hide. Many small fish like neon tetrasember tetras, rainbowfish,  Otocinclus Catfish, Celestial Pearl danios, and Cardinal fish are good to have besides this plant. It also provides cover and food in the form of infusoria for the baby fry. You can also keep any shrimp with the plant but dwarf shrimps are the best ones to have. For snails, Crayfish and freshwater crab, this grass is perfect.

Tank requirements

it is a fast-growing plant so a minimum 10-gallon tank size is required. To have it in your tank, set the temperature between 20 and 26 °C, pH from 6 to 7, and hardness of the water should be from 2 to 25 dKH. Salinity levels should be under 8ppt. The grass can be kept in an aquarium either in the substrate or floating. Low to moderate lighting daily from 8 to 12 hours is best for the grass. If you keep the plant near a light source it will be greener and can also turn red under high light but keep in mind it can get burned too. The plant can live without carbon dioxide but fertilizers are important so use liquid fertilizer regularly. By keeping it in gentle water flow you can control the growth of the plant.


If you want it in the substrate divide its stem and plant it. It will grow into a new plant. do not plant the floating one into substrate because it will die. You can cut the stems of floating grass and let them float. 

Caring and maintaining

You just have to keep the growth in check. If they overgrow, they can block light for other plants in the tank. Trim the regularly, supply fertilizers with diligence you will be good t go. With age the lower portion of the stem becomes unappealing so remove it accordingly.

Reasons to have in your tank

There are plenty of reasons. The grass provides shelter to fry protecting them from predators. It removes all nutrients which are in excesses like heavy metals and toxins. B doing this guppy grass indirectly eliminating a chance of algal bloom. It provides a breeding ground for livebearers, shrimp, and egg scatterers. It is a food source for herbivores like Goldfish, Silver dollar fish, and Cichlids. It provides oxygenation in the tank. Biofilm is produced on guppy grass which is also a food source of shrimplets and baby fry.

It grows with great speed and can overrun the tank in no time if left unchecked. By overgrowing, it can block light. Its stem is pretty delicate and can break easily. The broken parts are also a problem because wherever they fall they grow into new plants. when planting ensures to give it proper time so it can acclimatize to the tank environment.


Guppy grass is one of the low maintenance plants to have in the aquarium. An excellent option for both experts and beginner aquarists. Hope you have got all the information you need b this article.


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