Rotala indica Indian Toothcup

Rotala indica is often confused with Rotala rotundifolia but is a distinct species native to the Indian subcontinent and parts of Southeast Asia. Its key characteristic is the bicoloured leaf: the upper surface is bright green and the underside is pale pink to lilac, which becomes more visible as stems sway gently in current. It is considerably more tolerant of hard water, higher pH, and low CO2 than most Rotalas, making it one of the best choices for beginners interested in the genus.

Light: Low to medium (20–50 PAR); adaptable, though medium light gives best leaf shape. CO2: Not required; optional CO2 at 10–20 mg/L improves growth speed. Fertiliser: Weekly balanced liquid fertiliser; tolerant of a wide nutrient range. Planting: Background groups of 5–9 stems spaced 2 cm apart; trim every 2–3 weeks. Growth: Moderate; 15–30 cm; compact and manageable even without CO2.