Salvinia natans
The fastest-growing floating plant. Two oval leaves above water trap a layer of water for absorption; root-like submerged leaf hangs below for shrimp and fry cover. Skim weekly or it doubles in a week. Hates dripping surface water, keep glass lids dry above it.
Floating Watermoss (Salvinia) (Salvinia natans) is a floating aquatic plant for the floating of a planted tank. It reaches 2–5 cm under good conditions and grows at a very fast rate. Light: low to high. CO₂: none. Target 18–30 °C, pH 6.0–8.0, and 2–20 dGH. Substrate: None, floats on surface, draws nutrients from water column. Propagate via division (snap apart at nodes).
Care at a glance
The fastest-growing floating plant. Two oval leaves above water trap a layer of water for absorption; root-like submerged leaf hangs below for shrimp and fry cover. Skim weekly or it doubles in a week. Hates dripping surface water, keep glass lids dry above it.
By Mike ElmiraUpdated 2 min read
Part of our complete guide to the planted aquarium.
The parameters that decide whether floating watermoss (salvinia) fits in your tank.
Salviniaceae
Floating
Floating
None, floats on surface, draws nutrients from water column
Division (snap apart at nodes)
Still warm ponds and ditches worldwide
Europe, Asia, Africa (warm temperate)
Tank-mate safety and the species this one is documented to thrive (or fail) alongside.
Hard-won lessons from the tank.
Keep glass lids dry — water dripping from condensation onto Salvinia leaves rots them within days. Run lights with 5 cm air gap between water surface and bulbs to prevent leaf-cooking from heat. Provides shrimplet and fry refuge unmatched by any other floating plant — the dangling submerged leaves form a literal forest of hiding spots.
What can go wrong and how to spot it.
Failure modes, in order of how dramatic the fix is.
Yellow surface leaves: iron deficiency. Brown crispy edges: humidity too low (lid evaporation cooking the leaves). Slow growth: low nutrients or too cool.
Salvinia OUTCOMPETES algae — it's used in algae fights as a fast nutrient sponge. The submerged 'root' surface harbours biofilm that shrimplets graze.
The practical routine, read top to bottom.
Water column feeder via the underwater 'root-like leaf' (technically a modified leaf, not a root). Standard fertiliser dosing is enough. Iron deficiency shows as yellowing of the surface leaves.
Skim weekly with a net — Salvinia doubles in a week under good light. Aim for 50–70% surface coverage; full coverage blocks light to plants below.
Where it comes from, how it behaves, and the variants you'll see at retail.
Where it lived before it came home.
Floating on still and slow-moving fresh waters across Europe, Asia, and Africa. Pond and lake surface plant; not bottom-rooting.
All of Salvinia's life is essentially emersed — the leaves float ON the surface. Strictly speaking, there's no submerged form.
Salvinia doesn't flower — it's a fern and reproduces via spores. In aquariums it spreads exclusively by vegetative division (snapping at nodes).
The named cultivars and the lookalikes worth flagging.
S. natans is the most common. S. minima (smaller, more tropical) and S. cucullata (cupped leaves, larger) also sold as 'salvinia'. S. molesta is invasive and banned in many jurisdictions — check labels carefully.
Often confused with Frogbit (Limnobium laevigatum — larger round leaves with visible roots), Duckweed (Lemna minor — much smaller, single-leaf), and Azolla (smaller, more delicate). Salvinia has paired oval leaves with visible 'hair' tufts on the upper surface.
Direct answers to the questions search engines and AI assistants surface most often about this species.
CO₂ requirement: none. Light requirement: low to high. Under low-tech conditions the plant grows at a very fast rate.
Floating Watermoss (Salvinia) (Salvinia natans) needs low to high light. Run a photoperiod of 6–8 hours; longer photoperiods invite algae unless CO₂ and dosing are dialled in.
Position: floating. Substrate: None, floats on surface, draws nutrients from water column It typically reaches 2–5 cm.
Propagation method: Division (snap apart at nodes). Floating Watermoss (Salvinia) is a floating plant.
Target 18–30 °C, pH 6.0–8.0, and 2–20 dGH. Flow tolerance: still to low.
Difficulty: 1/5. Almost unkillable, a solid first-tank choice.
A planted tank is a system. Pair this plant with one entry from each other pillar to plan the whole scape.
