Rotala rotundifolia

Water parameters

Light and nutrients

Substrate type: nutrient preferred. Propagation: stem cuttings.

Substrate compatibility

With fish

Origin and habitat

Native to South and Southeast Asia, found in marshes, rice paddies, ditches, and shallow waterways across India, China, Vietnam, Thailand, and neighboring countries. The species (Rotala rotundifolia) is one of the most popular stem plants in the aquascaping hobby worldwide. The name 'rotundifolia' (round-leaved) describes the emersed form; submerged leaves are narrow and elongated. Under high light, the submerged leaves develop vivid pink to red coloring, especially at the stem tips. Multiple cultivars exist: 'Green' (stays green under most conditions), 'H'Ra' (Vietnamese form with intense red), 'Orange Juice' (orange-tinted), and 'Colorata' (reddish). A staple background plant in competition aquascapes. The species is one of the most commonly featured background plants in international aquascaping competitions (IAPLC, AGA), appearing in winning entries year after year. Its versatility across a range of conditions and the ability to produce vivid color with moderate effort make it the workhorse red stem plant of the hobby. Tissue culture specimens are available from every major aquatic plant producer.

Care notes

Moderate. Grows in low to high light, but the red coloring that makes R. rotundifolia popular only appears under moderate to high light with CO2. Under low light, the plant grows but stays green. CO2 at 20-30 ppm combined with high light and iron supplementation produces the most vivid pink-red tops. Plant stems in dense groups of 10+. Growth is moderate to fast; trim tops weekly and replant for progressively bushier growth. The small, fine leaves create a soft, feathery texture in the background. Nutrient requirements: moderate to high. Iron is critical for red color. Nitrate in the 5-15 ppm range produces better reds than very high nitrate (above 20 ppm). Temperature: 22–28°C. pH 6.0-7.5. Soft to moderately hard water. R. rotundifolia is the default recommendation for keepers who want a red background plant that's achievable without extreme demands. It's more forgiving than R. macrandra or Alternanthera while still producing attractive color under good conditions. Available everywhere from pet stores to specialty retailers.

Further reading

• Why your red plants won't turn red
• Keeping shrimp with fish: what works
• CO2 injection for planted tanks: what it costs, what it does, and when to skip it