Rotala macrandra

Rotala macrandra is native to the wetlands, paddy fields, and stream margins of southern India, where it grows as a marginal or semi-submerged plant in warm, soft, tropical water. When cultivated submerged under high light and CO2, it develops large, undulating, brilliant magenta-to-crimson leaves that are unmatched in colour intensity among aquarium stem plants. The delicate, translucent quality of the leaves — which appear almost to glow in transmitted light — makes it the star of high-end aquascaping compositions. However, this extraordinary visual performance comes at the cost of extremely demanding cultivation requirements. Rotala macrandra is among the most sensitive aquarium plants, reacting poorly to any deviation from optimal soft, slightly acidic water with high CO2, intense light, and rich but balanced nutrition. Even minor deficiencies or parameter fluctuations cause the translucent leaves to become small, pale, or papery and to deteriorate rapidly. Multiple varieties and cultivars exist, including 'Narrow Leaf', 'Green', and the exceptionally vivid 'Bangladesh', each with slightly different leaf forms and colour expressions. It is a species that separates casual planted-tank enthusiasts from dedicated aquascaping practitioners.

Placement Reserved for the background of large, high-tech aquariums. Plant in tight groups of 5–8 stems. The large, colourful leaves need space to develop fully without crowding from neighbouring plants.

Lighting Very high lighting (80–130 PAR) is required for maximum red and magenta colouration. Anything less produces pale, smaller leaves and weak growth. Use high-output LEDs or twin T5 fixtures.

CO2 & Fertilisation CO2 injection at 25–35 ppm is mandatory. Use Estimative Index or ADA-style dosing with elevated iron (0.3–0.5 ppm), potassium, and complete trace elements. Soft water (below 6° GH) and pH 5.5–6.5 are critical. Calcium and magnesium must be balanced.

Propagation Top cuttings of 6–8 cm replanted gently in fine substrate. Roots form slowly over 2 weeks. Handle stems with extreme care — the fragile leaves bruise and rot easily. Replant immediately into conditioned water.

Trimming Trim every 2–3 weeks, cutting just above a node. Replant the colourful, healthy tops and discard deteriorated lower sections. Avoid trimming during ongoing deficiency episodes — stabilise conditions first, then trim.