Whip Rotala

Rotala wallichii is the finest-leaved of the commonly available red rotalas, producing densely packed needle-like leaves that turn pink to orange-red under strong light. Each stem resembles a soft bottlebrush, and a well-grown group in the midground or background creates a texture that contrasts sharply with broad-leaf plants. Flowgrow reports an optimum temperature of 24 to 28 °C and pH from 5 to 7, with medium to high light and CO2 at 20–40 mg/l. Without CO2 injection the lower half of each stem loses its leaves and the colour shifts to dull olive. Growth is fast in optimal conditions, needing trimming every five to seven days. The stems branch readily when the top is cut, so propagation is simply a matter of replanting the trimmings. Carbonate hardness should stay below 12 dKH — harder water causes leaf distortion and slows growth. Nitrate levels around 10–50 mg/l and phosphate 0.1–3 mg/l keep the colour intense; low nitrate tends to deepen the red but also reduces stem thickness. Rotala wallichii is suitable for nano tanks as well as larger layouts because the stems stay relatively thin and can be grouped tightly. The difficulty is rated difficult on Flowgrow, which is accurate for keepers moving from easy stem plants to something that demands consistent CO2 and lighting discipline.