Rotala Rotundifolia

Rotala rotundifolia is widespread across tropical and subtropical Asia, including India, Sri Lanka, China, and much of Southeast Asia, inhabiting rice paddies, shallow pools, streams, and seasonally flooded ground. It is one of the most commonly sold aquarium plants globally and is often the first Rotala species an aquarist encounters. The submerged leaves are narrow and elongated — quite different from the round emersed leaves that give the species its name — and transform from green to beautiful shades of pink and red under stronger lighting and CO2 supplementation. Unlike most other red stem plants, R. rotundifolia is tolerant of moderate hardness and a relatively broad pH range, enabling it to colour up partially even in moderately hard water. Its fast growth rate makes it an excellent nutrient exporter and a reliable plant for establishing biological equilibrium in new tanks. In aquascaping it is widely used in the background or as a colour accent in both nature aquarium and Dutch styles. The cultivar 'Blood Red' is selected for even more intense colouration.

Placement Suit to the background or mid-background of most aquariums. Plant in groups of 7–10 stems for the most impactful colour display. Works well alongside green stem plants such as Rotala rotundifolia 'Green' or Bacopa.

Lighting Moderate-to-high lighting (40–80 PAR) will produce progressively deeper pink and red colouration. Even under moderate light without CO2 the plant grows well and shows at least some pink colour in the upper stem tips.

CO2 & Fertilisation CO2 injection at 20–30 ppm greatly enhances colour intensity and growth rate. Regular fertilisation with macros and micros is beneficial. Iron at 0.1–0.3 ppm maintains vibrant colour.

Propagation Top cuttings 6–10 cm replant effortlessly. Side shoots emerge reliably after trimming. One of the easiest Rotala species to propagate. Roots establish within 7 days in warm conditions.

Trimming Trim every 2–3 weeks. Replant colourful top cuttings and remove lower bare stems. Regular trimming encourages branching and a fuller appearance. This species recovers quickly from even aggressive cutting.