Floating Moss

What is sold as Salvinia natans in the aquarium trade is almost certainly not the true S. natans. The Flowgrow database, an authoritative European aquatic plant reference, states plainly that this species is 'probably not cultivated in aquariums, name erroneously used for another plant.' The plant in circulation is almost always Salvinia auriculata or one of its close relatives, which grow in tropical conditions rather than the cool temperate waters the true S. natans requires.

The practical difference matters for cultivation: true S. natans is a European and Asian seasonal fern that dies back in winter and regenerates from spores. The tropical look-alike grows year-round, spreads by fragmentation, and tolerates warm water that would cause the genuine species to decline. Since the plant in the trade behaves like a tropical Salvinia, the care guidelines reflect that.

Like other floating ferns, it needs no CO₂ or special fertiliser, draws nutrients directly from the water, and grows quickly enough to require weekly thinning. Each leaf pair is oblong and slightly cupped, with water-repellent hairs on the upper surface. The short roots that hang below provide cover for fry in open-top tanks.