Spirodela polyrhiza

Spirodela polyrhiza is the largest genus of true duckweeds, producing flat, round fronds up to 1 cm across with 7–21 roots per frond. The underside of each frond carries reddish-purple anthocyanin pigments that are visible in shallow water. It grows slightly more slowly than Lemna minor, making it somewhat easier to manage, while still providing effective surface coverage and nutrient uptake. Its larger frond size makes it a more substantial food offering for herbivorous fish.

Light: Low to medium surface light; grows under most aquarium lighting. CO2: Not required; absorbs nutrients directly from the water. Planting: Place on the water surface; no planting required. Maintenance: Thin the colony regularly; the larger fronds are easier to scoop out than smaller duckweed species. Note: Tolerates a wide temperature range including cool water; suitable for both tropical and temperate tanks.