Rotala rotundifolia
Rotala rotundifolia
Also known asPink rotala · Roundleaf toothcup · Dwarf rotala
Water parameters
Light and nutrients
Substrate type: nutrient preferred. Propagation: stem cuttings.
Substrate compatibility
| Substrate | pH effect | Nutrient load |
|---|---|---|
| Aquasoil (ADA Amazonia) | lowers pH | very high |
| Mineralized clay substrate (Seachem Fluorite) | neutral / inert | moderate |
| Dirted tank (mineralized topsoil) (DIY soil substrate) | slightly acidic | very high |
| Inert sand (Pool filter sand) | neutral / inert | none |
With fish
Origin and habitat
One of the most popular aquascaping stem plants in the world, Rotala rotundifolia (Buch.-Ham. ex Roxb.) Koehne, family Lythraceae, native broadly across tropical and subtropical Asia, from India and Bangladesh through the Himalaya, China, Japan, Taiwan and Indochina, in marshes, rice paddies, ditches and shallow water. The name rotundifolia, round-leaved, describes only the emersed form; submerged the leaves are narrow and lanceolate. Under strong light the submerged leaves flush vivid pink to red, brightest at the stem tips. Several cultivars are traded, including 'Green', the Vietnamese 'H'Ra' with intense red, 'Orange Juice', 'Colorata' and 'Ceylon'. It is the workhorse red background plant of competition aquascaping, appearing in winning IAPLC and AGA tanks year after year. It is also a rice-paddy weed at home and an introduced invasive in the southern US, classed as a Category 2 invasive in Florida where it forms dense surface mats.
Care notes
Moderate. It grows from low to high light, but the red that makes it popular only shows under moderate to strong light with CO2; in low light it grows green. The brightest pink-red comes from high light plus CO2 around 20 to 30 ppm, plenty of iron, and a deliberately low nitrate (around 5 mg/L) with higher phosphate, and shifting the fertiliser balance shifts the hue from pink to yellow. Plant in dense groups of ten or more, trim the tops weekly and replant for a progressively bushier stand; the fine leaves give a soft feathery background. Keep it around 22–28°C in soft to moderately hard water. It is the default red background plant for anyone wanting colour without the demands of R. macrandra or Alternanthera, more forgiving while still colouring well. Because it is an aggressive weed and established invasive, never release it or pour tank water into waterways. It is an ornamental, not a crop, so it is unsuited to media-bed aquaponics or hydroponics.