Rotala rotundifolia

Quick facts

Max height

30 cm

Growth rate

fast

Difficulty

intermediate

Placement

midground, background

Propagation

stem cuttings

Water parameters

Temperature

18–28°C

pH

5.5 to 7.5

Hardness

0 to 15 dGH

Light and nutrients

Lighting

high

CO2

not required, but boosts growth and color

Substrate

nutrient preferred

Feeding

feeds from both water column and roots (liquid ferts plus root tabs)

Substrate

What this plant roots into (or attaches to). The substrate affects both plant nutrition and water chemistry; see each linked page for full effects.

This plant feeds primarily from the water column, so substrate choice matters more for its fish-tank compatibility than for plant nutrition.

With fish

Plant-eating fish

safe with plant-eating fish (tough leaves or unpalatable)

Diggers (corydoras, loaches)

fine - root system or attachment style handles it

Root-disturbing fish

tolerates fish that disturb roots

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 actually 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

• CO2 injection for planted tanks: what it costs, what it does, and when to skip it