Najas guadalupensis
A fast-growing, fine-leaved stem that thrives floating or anchored. The breeder's secret weapon: shrimplets and fry hide in its dense foliage, and it strips nitrate from new tanks fast. Snaps easily during gravel-vac; replant the fragments.
Guppy Grass (Najas guadalupensis) is a stem (rootless) aquatic plant for the background or floating of a planted tank. It reaches 30–60 cm under good conditions and grows at a very fast rate. Light: low to high. CO₂: not required. Target 15–28 °C, pH 6.0–8.0, and 3–20 dGH. Substrate: Optional — grows free-floating or weighted in substrate. Propagate via any broken segment grows on.
Care at a glance
A fast-growing, fine-leaved stem that thrives floating or anchored. The breeder's secret weapon: shrimplets and fry hide in its dense foliage, and it strips nitrate from new tanks fast. Snaps easily during gravel-vac; replant the fragments.
Updated 1 min read
Part of our complete guide to the planted aquarium.
Leaves yellowing, pitting, or new growth coming in pale or twisted? Work out what it’s short of in our plant deficiency guide.
The parameters that decide whether guppy grass fits in your tank.
Hydrocharitaceae
Stem (rootless)
Background or floating
Optional — grows free-floating or weighted in substrate
Any broken segment grows on
Americas (Caribbean and Gulf)
Americas (Caribbean and Gulf)
Tank-mate safety and the species this one is documented to thrive (or fail) alongside.
Weighing it against something similar? Compare Guppy Grass head to head:
Direct answers to the questions search engines and AI assistants surface most often about this species.
CO₂ requirement: not required. Light requirement: low to high. Under stable injected CO₂ the plant grows at a very fast rate.
Guppy Grass (Najas guadalupensis) needs low to high light. Run a photoperiod of 6–8 hours; longer photoperiods invite algae unless CO₂ and dosing are dialled in.
Position: background or floating. Substrate: Optional — grows free-floating or weighted in substrate It typically reaches 30–60 cm.
Propagation method: Any broken segment grows on. Guppy Grass is a stem (rootless) plant.
Target 15–28 °C, pH 6.0–8.0, and 3–20 dGH. Flow tolerance: low to medium.
Difficulty: 1/5. Almost unkillable, a solid first-tank choice.
A planted tank is a system. Pair this plant with one entry from each other pillar to plan the whole scape.
