Cryptocoryne undulata 'Red'
Cryptocoryne undulata
Also sold as Crypt undulata red · C. undulata
Synonyms Crypt undulata
Cryptocoryne undulata 'Red' (Cryptocoryne undulata) is a rosette plant for the midground, growing to about 25 cm (9.8 in) at a slow pace. It wants 68–82°F (20–28°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 | 68–82°F (20–28°C) |
| Max height | 25 cm (9.8 in)Grown submersed, left to mature, never trimmed. |
| Growth rate | Slow |
| Placement | planted in the midground |
| pH | 6–8 |
Before it goes in
- Cryptocoryne undulata 'Red' 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.
- Expect it to melt back a few weeks after planting and regrow from the roots — pulling it out at that point is the mistake.
- At about 25 cm (9.8 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. Cryptocoryne undulata 'Red' 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.
How big does it get?
About 25 cm (9.8 in) tall when it is mature and untrimmed, growing slowly, after roughly 6 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 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
| Cryptocoryne undulata 'Red' | Cryptocoryne albida | Cryptocoryne nurii | |
|---|---|---|---|
| Light | Low | Low | Low |
| CO₂ | Not needed | Not needed | Not needed |
| Max height | 25 cm | 25 cm | 25 cm |
| Difficulty | Easy | Easy | Easy |
More plants
Sources (2) · checked Sep 2026
- Max height, Difficultytropica.com
- Meltingbuceplant.com