Hydrocotyle tripartita 'Japan'
Hydrocotyle tripartita
Also sold as Hydrocotyle sp. Japan · Tripartita
Synonyms Dwarf pennywort · Hydrocotyle japan
Hydrocotyle tripartita 'Japan' (Hydrocotyle tripartita) is a carpeting plant for the foreground and the midground, growing to about 6 cm (2.4 in) at a moderate pace. It wants 68–82°F (20–28°C), medium light and CO₂ if you have it, and counts as a medium-difficulty 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 | Medium |
| Temperature | 68–82°F (20–28°C) |
| Max height | 6 cm (2.4 in)Grown submersed, left to mature, never trimmed. |
| Growth rate | Moderate |
| Placement | planted in the foreground and the midground |
| pH | 6–7.5 |
Before it goes in
- Hydrocotyle tripartita 'Japan' 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.
- In too little light it stretches upward instead of running sideways, and the carpet never closes.
- It stays around 6 cm (2.4 in), low enough to keep the front glass clear.
- Its leaves are soft: Goldfish, Common Pleco and Molly will eat it.
- It needs about 3 weeks to root. Fish that dig — Goldfish and Common Pleco — will lift it before then.
Can it grow without CO₂?
Yes, but slowly. Hydrocotyle tripartita 'Japan' 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. Below it, this one stretches instead of spreading.
How big does it get?
About 6 cm (2.4 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 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
| Hydrocotyle tripartita 'Japan' | Cryptocoryne parva | Littorella uniflora | |
|---|---|---|---|
| Light | Medium | Low | Low |
| CO₂ | Recommended | Recommended | Not needed |
| Max height | 6 cm | 6 cm | 6 cm |
| Difficulty | Medium | Medium | Easy |
More plants
Sources (1)
- Light, Max height, Growth in low lighttropica.comSep 2026