Nuphar japonica

Nuphar japonica grows naturally in the ponds and slow rivers of Japan and Korea, where it is a culturally significant plant depicted in traditional art. In the aquarium it produces distinctive, arrow-shaped or sagittate submerged leaves with prominent, parallel veining on deep-green to olive-green leaf blades, rising on long petioles from a stout horizontal rhizome. It prefers cooler temperatures of 15–22°C, making it ideal for subtropical setups. Under warm tropical conditions it will survive but grow sluggishly. Achieving the rhizome's full potential requires patient root fertilisation.

Light: Medium (30–50 PAR); grows well under standard aquarium lighting. CO2: Beneficial; injection promotes larger, more vigorous leaves. Fertiliser: Root tab alongside the rhizome every 3 months; liquid fertiliser monthly. Planting: Lay rhizome horizontally on the substrate surface or lightly anchored; background placement. Growth: Moderate in cool water (15–22°C); slows in warm water; reaches 30–60 cm; trim old leaves at the rhizome.