Lobelia cardinalis 'Mini'
Lobelia cardinalis
Synonyms Dwarf lobelia · Cardinal plant · Cardinal flower · Lobelia mini
Lobelia cardinalis 'Mini' (Lobelia cardinalis) is a stem plant for the foreground and the midground, growing to about 10 cm (3.9 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 | 10 cm (3.9 in)Grown submersed, left to mature, never trimmed. |
| Growth rate | Fast |
| Placement | planted in the foreground and the midground |
| pH | 6–7.5 |
Before it goes in
- Lobelia cardinalis 'Mini' 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.
- Its leaves are medium: Goldfish, Electric Yellow Lab and Colombian Ramshorn Snail will eat it.
Can it grow without CO₂?
Yes, but slowly. Lobelia cardinalis 'Mini' 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 10 cm (3.9 in) tall when it is mature and untrimmed, growing fast, after roughly 3 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
| Lobelia cardinalis 'Mini' | AR Mini | Staurogyne 'Porto Velho' | |
|---|---|---|---|
| Light | Medium | Medium | Low |
| CO₂ | Recommended | Recommended | Recommended |
| Max height | 10 cm | 12 cm | 10 cm |
| Difficulty | Medium | Medium | Medium |
More plants
Sources (2) · checked Sep 2026
- Light, Growth in low lightaquasabi.com
- CO₂tropica.com