Pygmy Chain Sword
Helanthium tenellum
Also sold as Narrow leaf chain sword · E. tenellus
Synonyms Echinodorus tenellus
Pygmy Chain Sword (Helanthium tenellum) is a carpeting plant for the foreground, growing to about 10 cm (3.9 in) at a moderate pace. It wants 68–82°F (20–28°C), low light and CO₂ if you have it, and counts as an easy plant to keep alive.
At a glance
| Type | Carpeting plant |
|---|---|
| Light | LowThe 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 | Easy |
| Temperature | 68–82°F (20–28°C) |
| Max height | 10 cm (3.9 in)Grown submersed, left to mature, never trimmed. |
| Growth rate | Moderate |
| Placement | planted in the foreground |
| pH | 6–7.5 |
Before it goes in
- Pygmy Chain Sword lives under a plain low-light LED — it does not need a planted-tank lamp to survive.
- 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.
- In too little light it stretches upward instead of running sideways, and the carpet never closes.
- It only colours up under strong light with CO₂; in a low-tech tank it stays green.
- 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.
Can it grow without CO₂?
Yes, but slowly. Pygmy Chain Sword 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?
Low light is enough — 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 10 cm (3.9 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
| Pygmy Chain Sword | Helanthium 'Quadricostatus' | Micro Sword | |
|---|---|---|---|
| Light | Low | Low | Medium |
| CO₂ | Recommended | Not needed | Recommended |
| Max height | 10 cm | 15 cm | 7 cm |
| Difficulty | Easy | Easy | Medium |
More plants
Sources (7) · checked Sep 2026
- Difficulty, Max heightaquariumbreeder.com
- Light, Difficultyaquariumswest.com
- Max height, Growth in low lightscaleandstem.com
- Light, Colortfhmagazine.com
- Meltingaquariumplantsfactory.com
- Growth in low lightaquariumplantsfactory.com
- Meltinggensou.sg