Downoi
Pogostemon helferi
Also sold as Daonoi
Synonyms Little star · Pogo helferi
Downoi (Pogostemon helferi) is a carpeting plant for the foreground, growing to about 8 cm (3.1 in) at a moderate pace. It wants 72–82°F (22–28°C), medium light and CO₂ if you have it, and counts as an advanced plant to keep alive.
At a glance
| Type | Carpeting plant |
|---|---|
| Light | MediumThe least light it survives in, not the light it looks best in. |
| CO₂ | RecommendedWhether it survives without added CO₂ — not whether CO₂ would help it grow faster. |
| Difficulty | Advanced |
| Temperature | 72–82°F (22–28°C) |
| Max height | 8 cm (3.1 in)Grown submersed, left to mature, never trimmed. |
| Growth rate | Moderate |
| Placement | planted in the foreground |
| pH | 6–7.5 |
Before it goes in
- Downoi needs medium light. Under a low-light LED it thins out instead of filling in.
- CO₂ is not required, but without it expect slow growth and a thinner result.
- It feeds through its roots, so in plain sand or gravel it needs root tabs; in an aquasoil it does not.
- Expect it to melt back a few weeks after planting and regrow from the roots — pulling it out at that point is the mistake.
- Its leaves are soft: Goldfish, Common Pleco and Molly will eat it.
- It needs about 4 weeks to root. Fish that dig — Goldfish and Common Pleco — will lift it before then.
- It counts as an advanced plant: it is not a first-tank pick.
Can it grow without CO₂?
Yes, but slowly. Downoi is listed as CO₂-recommended, not CO₂-required: without injection it survives and grows, it just takes far longer to fill in.
How much light does it need?
Medium light — and that is the survival line, not the “it looks better” line.
How big does it get?
About 8 cm (3.1 in) tall when it is mature and untrimmed, growing at a moderate pace, after roughly 4 weeks to root in.
Why is it melting?
That is normal for this one. It usually drops its existing leaves a few weeks after planting and regrows from the roots — leave it in place and it comes back.
Will my fish eat it?
Its leaves are soft, so some will: Goldfish, Common Pleco and Molly.
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 Cryptocoryne wendtii.
- Animals that share its temperature range and will not eat or uproot it: Betta, Cherry Shrimp, Angelfish and Bristlenose Pleco.
Often compared with
| Downoi | Dwarf Hairgrass | Ranunculus inundatus | |
|---|---|---|---|
| Light | Medium | Medium | Medium |
| CO₂ | Recommended | Recommended | Recommended |
| Max height | 8 cm | 8 cm | 8 cm |
| Difficulty | Advanced | Easy | Medium |
More plants
Sources (1)
- Light, CO₂buceplant.comSep 2026