Guppy Grass
Najas guadalupensis
A fast, stringy plant that floats or plants anywhere - superb fry and shrimp cover.
| Care Difficulty | Beginner |
| Lighting | Low to Medium |
| CO2 Requirement | Not required |
| Growth Rate | Very Fast |
| Placement | Background/Floating |
Overview
Guppy Grass (Najas guadalupensis) is a fast, stringy plant that floats or plants anywhere - superb fry and shrimp cover. It is a beginner plant to grow, which makes it a great pick for beginners and low-tech tanks.
This guide explains, in plain language, how to grow Guppy Grass well: what it looks like, how much light it wants, whether it needs CO2, how to plant and place it, how to make more of it for free, and the simple mistakes to avoid.
Appearance & Growth
A fast, stringy plant that floats or plants anywhere - superb fry and shrimp cover.
It is a very fast grower and is normally used in the background/floating of the aquarium. Fast growth means you will trim it often, but it also soaks up lots of nutrients and helps keep algae away.
Lighting
Guppy Grass does best under low to medium light. Low to medium light is plenty, so a basic aquarium LED will keep it happy.
Keep the lights on a timer for about 6 to 8 hours a day. Leaving lights on longer usually grows more algae, not more plant, so add light time slowly and watch for any green film.
CO2 & Fertilising
CO2: Not required. This plant grows fine without added CO2, so it suits simple, low-tech tanks.
Feed it with an all-in-one liquid fertiliser (such as API Leaf Zone) added to the water each week. If leaves turn yellow, get holes, or stop growing, that is almost always a lack of nutrients, not a disease.
Planting & Placement
Plant Guppy Grass in the substrate, spacing stems or plants slightly apart so light and water can reach them all. Root tabs in the substrate help it settle and grow strongly.
How to Propagate (Make More)
It is very easy to propagate: snip the top few centimetres off a healthy stem and push the cutting into the substrate. Each cut stem then branches and grows bushier.
Swapping cuttings is one of the best parts of the hobby - over time a single healthy plant can fill your tank and stock a few more.
Common Problems & How to Fix Them
The most common problem is algae growing on the leaves. This usually means too much light, not enough nutrients, or weak water flow - not a problem with the plant. Lower the light a little, add fertiliser, and improve flow.
Some leaf loss right after planting is normal while the plant gets used to living underwater - keep your light, CO2 and fertiliser steady and new growth will follow. Always remove dead or rotting leaves quickly to keep the plant and water healthy.
Is Guppy Grass Right for Your Tank?
Guppy Grass is an easy, rewarding plant that fits almost any freshwater aquarium, including first tanks and low-tech setups. Pair it with our other plant and aquascaping guides to build a lush, healthy planted tank.