Giant Hairgrass
Eleocharis montevidensis
Also sold as Giant hair grass
Synonyms Sand spikerush
Giant Hairgrass (Eleocharis montevidensis) is a rosette plant for the background, growing to about 42.5 cm (16.7 in) at a moderate pace. It wants 64–82°F (18–28°C), low light and no CO₂, and counts as an easy plant to keep alive.
At a glance
| Type | Rosette plant |
|---|---|
| Light | LowThe least light it survives in, not the light it looks best in. |
| CO₂ | Not neededWhether it survives without added CO₂ — not whether CO₂ would help it grow faster. |
| Difficulty | Easy |
| Temperature | 64–82°F (18–28°C) |
| Max height | 42.5 cm (16.7 in)Grown submersed, left to mature, never trimmed. |
| Growth rate | Moderate |
| Placement | planted in the background |
| pH | 6–7.5 |
Before it goes in
- Giant Hairgrass lives under a plain low-light LED — it does not need a planted-tank lamp to survive.
- It grows without CO₂.
- It feeds through its roots, so in plain sand or gravel it needs root tabs; in an aquasoil it does not.
- In too little light it stretches: long bare stems between leaves instead of a bushy plant.
- At about 42.5 cm (16.7 in) it belongs behind everything shorter — planted at the front it hides the rest of the scape and shades it.
- Its leaves are medium: Goldfish, Electric Yellow Lab and Colombian Ramshorn Snail will eat it.
Can it grow without CO₂?
Yes. Giant Hairgrass does not need CO₂ at all.
How much light does it need?
Low light is enough — and that is the survival line, not the “it looks better” line. Below it, this one stretches instead of spreading.
How big does it get?
About 42.5 cm (16.7 in) tall when it is mature and untrimmed, growing at a moderate pace, after roughly 3 weeks to root in.
Will my fish eat it?
Its leaves are medium, so some will: Goldfish, Electric Yellow Lab and Colombian Ramshorn Snail.
What it goes with
- Plants that run on the same light and CO₂, so they can share a tank without one of them being the odd one out: Hygrophila corymbosa 'Siamensis', Water Sprite, Anubias nana 'Petite' and Frogbit.
- Animals that share its temperature range and will not eat or uproot it: Betta, Cherry Shrimp, Angelfish and Bristlenose Pleco.
Often compared with
| Giant Hairgrass | Umbrella Hair Grass | Corkscrew Val | |
|---|---|---|---|
| Light | Low | Medium | Low |
| CO₂ | Not needed | Recommended | Not needed |
| Max height | 42.5 cm | 40 cm | 40 cm |
| Difficulty | Easy | Easy | Easy |
More plants
Sources (4) · checked Sep 2026
- Max heightaquasabi.com
- Growth in low lightmodernaquarium.com
- Growth in low lighttankbud.com
- Max heighttropica.com