Hydrilla verticillata

Hydrilla verticillata is native to Asia, Europe, and Africa and is one of the most adaptable submerged aquatic plants known, capable of growing in very low light, across a wide temperature range, and in fresh to slightly brackish water. Its slender stems bear whorls of small, serrated, bright-green leaves that are denser and more compact than those of Egeria, creating a finely textured, bushy mass. In the aquarium it grows very rapidly under even minimal light, making it a superb low-tech oxygenator and water purifier. Its dense growth provides outstanding cover and spawning habitat for small fish and invertebrates. Regular trimming prevents it from overwhelming the aquarium.

Light: Low to medium (15–50 PAR); one of the most shade-tolerant oxygenating stem plants. CO2: Not required; grows vigorously on ambient CO2 in still and flowing water alike. Fertilisation: Minimal — water column feeder; occasional dilute liquid fertiliser every 2 weeks. Placement: Background in dense bunches; trim tops regularly and replant to maintain bushy, compact growth. Propagation: Stem cuttings of any length; simply replant trimmed sections immediately.