Ammannia gracilis
Synonyms Delicate ammannia · Ammania gracilis
Ammannia gracilis is a stem plant for the background, growing to about 50 cm (19.7 in) at a fast pace. It wants 72–82°F (22–28°C), medium light and pressurised CO₂, and counts as a medium-difficulty plant to keep alive.
At a glance
| Type | Stem plant |
|---|---|
| Light | MediumThe least light it survives in, not the light it looks best in. |
| CO₂ | RequiredWhether it survives without added CO₂ — not whether CO₂ would help it grow faster. |
| Difficulty | Medium |
| Temperature | 72–82°F (22–28°C) |
| Max height | 50 cm (19.7 in)Grown submersed, left to mature, never trimmed. |
| Growth rate | Fast |
| Placement | planted in the background |
| pH | 6–7.5 |
Before it goes in
- Ammannia gracilis needs medium light. Under a low-light LED it thins out instead of filling in.
- Pressurised CO₂ is required — without injection it melts away rather than settling in.
- In too little light it stretches: long bare stems between leaves instead of a bushy plant.
- It only colours up under strong light with CO₂; in a low-tech tank it stays green.
- At about 50 cm (19.7 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?
No. Ammannia gracilis needs pressurised CO₂; without it, it melts back rather than settling in.
How much light does it need?
Medium light — and that is the survival line, not the “it looks better” line. Below it, this one stretches instead of spreading. Colour is a separate question: it only turns red under strong light with CO₂.
How big does it get?
About 50 cm (19.7 in) tall when it is mature and untrimmed, growing fast, after roughly 2 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: Water Sprite, Anubias nana 'Petite', Cryptocoryne wendtii and Dwarf Hairgrass Mini.
- Animals that share its temperature range and will not eat or uproot it: Betta, Cherry Shrimp, Angelfish and Bristlenose Pleco.
Often compared with
| Ammannia gracilis | Ammannia crassicaulis | Ammannia pedicellata 'Golden' | |
|---|---|---|---|
| Light | Medium | Medium | Medium |
| CO₂ | Required | Recommended | Recommended |
| Max height | 50 cm | 40 cm | 40 cm |
| Difficulty | Medium | Medium | Medium |
More plants
Sources (1)
- Lightaquariumcoop.comSep 2026