Guppy Grass

Najas guadalupensis, known among aquarists as "guppy grass", is a heavily branching aquatic plant with thin, narrow leaves. It grows fast, quickly absorbs excess nutrients from the water and competes strongly with algae. Its dense, tangled structure provides an excellent hiding place for guppy, Endler and shrimp fry, which makes it a staple of fry and breeding tanks. Its stems are brittle; broken pieces soon grow into new plants.

Do not release into the wild: It is a fast-spreading plant; excess material must not be thrown into natural waters.

• It can be left floating freely; used this way it forms a dense mass.
• If desired, the stems can be planted by burying them 3–4 cm in the substrate or wedging them between rocks.

• Light: Moderate; it also survives in low light.
• CO₂: Not required.
• Fertilizer: Usually not needed; it takes its nutrients from the water.
• Trimming: Because it grows fast it needs frequent thinning; remove the excess from the aquarium and take care that brittle fragments do not get sucked into the filter.