Myriophyllum mattogrossense: the feathery green foxtail for fast growth
Family Haloragaceae · South America
Soft, feathery whorls and rapid growth make the green foxtail one of the most useful plants for a new tank — a living nutrient sponge that helps tip the balance against algae.
A South American foxtail
Myriophyllum mattogrossense takes its name from the Mato Grosso region of Brazil and is a genuine tropical species from South American wetlands — often sold as Myriophyllum ‘Guyana’. That matters, because the genus Myriophyllum also contains some of the world’s most notorious invasive weeds (parrot’s feather and Eurasian watermilfoil among them), so responsible disposal is worth taking seriously. This warm-water tropical species is unlikely to establish in cold climates, but invasive risk in warm regions is not zero, so treat it with the same caution.
Never release aquarium plants into the wild or compost them where runoff can reach waterways — bag and bin unwanted trimmings.
Soft feathery whorls
Each node carries a whorl of finely divided, feather-like leaves, giving the whole stem the soft foxtail texture that makes it so popular. Colour is a bright, fresh green; unlike the colour stems on this site it is grown for form and movement rather than red or purple pigment. In good flow the feathery foliage sways beautifully.
How to keep it
The foxtail is fast and feeds heavily from the water column, which is the source of both its main use and its main weakness. Give it decent light and a steady supply of nutrients — iron in particular — and it grows quickly and stays a rich green. Let iron and micros run short and the fine foliage pales and thins from chlorosis, which shows up faster here than in tougher-leaved plants precisely because growth is so rapid.
Because it takes up nutrients so quickly, it is genuinely useful for tipping a new tank’s balance towards plants and away from algae — fast-growing stems acting as nutrient sinks is a well-founded principle, not just folklore. See what iron and micro levels different all-in-ones provide in the fertiliser comparison calculator.
| Parameter | Value |
|---|---|
| Lighting | Medium to high — keeps growth dense and green |
| CO2 | Beneficial; grows without but faster and fuller with |
| Temperature | 22–28°C |
| pH | 5.5–7.5 |
| Hardness | Soft to medium |
| Fertiliser | Fast feeder — needs iron and a full micro mix to stay green |
| Substrate | Any; feeds heavily from the water column |
| Growth rate | Fast |
| Placement | Background |
| Difficulty | Medium |
Texture, movement and a new-tank workhorse
Its feathery texture contrasts strikingly with broad-leaved plants, and a dense stand makes a soft green backdrop. Many scapers use it as a temporary filler in the first weeks of a layout — fast growth and heavy uptake help outcompete algae — then thin or remove it as slower, choicer plants take over.
Cuttings root anywhere
Cut and replant tops; they root readily and grow away fast. It can also grow unplanted, drawing everything it needs from the water. Because growth is quick, trim regularly — and bag the trimmings for the bin rather than passing dense mats to the compost.
What goes wrong
Pale new growth points specifically to iron (an immobile nutrient the plant cannot shift from old leaves to new), while general thinning and crumbling follows a wider micronutrient shortage — the fine, fast-growing foliage shows both first. Leggy stems with sparse whorls usually mean more light, though CO2 or nutrient limitation can contribute. Because the foliage is so fine, it readily traps detritus and can host algae in a low-flow or dirty tank, so good flow and clean water keep it looking its best.
More plants in this series
- Hornwort — another fast feathery nutrient sponge
- Water sprite — a fast, forgiving filler
- Guppy grass — a rampant nutrient exporter