Hygrophila polysperma Indian Waterweed

Hygrophila polysperma is one of the most forgiving aquarium plants in existence, tolerating poor lighting, wide pH swings, hard or soft water, and temperatures from subtropical cool to tropical warm. Its oval to elliptic leaves are pale to mid-green and are produced rapidly along branching stems. In some jurisdictions it is considered invasive outdoors, so care should be taken with disposal. For aquarium use it is an invaluable beginner plant and a first-choice species for new tank cycling.

Light: Low to high (10–80 PAR); thrives under even the most basic aquarium lighting. CO2: Not required; one of the most tolerant plants with respect to CO2 levels. Fertiliser: Minimal fertilisation needed; benefits from weekly balanced liquid fertiliser. Planting: Background groups of 5–9 stems spaced 2–3 cm; trim every 1–2 weeks. Growth: Very fast; 15–40 cm; rapid growth aids nitrogen cycling in new aquariums.