Ludwigia arcuata
Also sold as Needle-leaf ludwigia · Arcuata
Synonyms Piedmont primrose-willow
Ludwigia arcuata is a stem plant for the background and the midground, growing to about 30 cm (11.8 in) at a fast pace. It wants 64–79°F (18–26°C), medium light and CO₂ if you have it, 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 | RecommendedWhether it survives without added CO₂ — not whether CO₂ would help it grow faster. |
| Difficulty | Medium |
| Temperature | 64–79°F (18–26°C) |
| Max height | 30 cm (11.8 in)Grown submersed, left to mature, never trimmed. |
| Growth rate | Fast |
| Placement | planted in the background and the midground |
| pH | 6–7.5 |
Before it goes in
- Ludwigia arcuata 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: 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 30 cm (11.8 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, but slowly. Ludwigia arcuata 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. Colour is a separate question: it only turns red under strong light with CO₂.
How big does it get?
About 30 cm (11.8 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
| Ludwigia arcuata | Ludwigia glandulosa | Ludwigia ovalis | |
|---|---|---|---|
| Light | Medium | Medium | Medium |
| CO₂ | Recommended | Recommended | Recommended |
| Max height | 30 cm | 30 cm | 30 cm |
| Difficulty | Medium | Medium | Medium |
More plants
Sources (2) · checked Sep 2026
- CO₂, Lightbuceplant.com
- CO₂cantonaquatics.com