Hydrocharis morsus-ranae

Hydrocharis morsus-ranae is native to Europe and Central Asia, where it colonises the still and slow-moving surfaces of ponds, lakes, and ditches. Its small, rounded to heart-shaped leaves float on the surface, resembling miniature lily pads, while long, feathery roots dangle below providing cover for fry, shrimp, and surface-feeding fish. It reproduces rapidly by sending out stolons from which daughter plantlets develop, quickly covering open water areas. In the aquarium it creates beneficial shading that reduces algae growth, moderates light intensity for shade-loving plants below, and provides natural spawning sites. It is best kept in tanks with gentle surface agitation and adequate surface light.

Light: Medium to high (40–80 PAR at the surface); floating habit means it accesses light directly. CO2: Not required; absorbs CO2 directly from the atmosphere. Fertilisation: Light liquid fertiliser every 1–2 weeks; roots absorb nutrients directly from the water column. Placement: Floating surface cover; thin regularly to maintain open swimming and light penetration below. Propagation: Produces stolons with daughter plantlets freely; remove excess plants to control coverage.