Butterfly fern

Salvinia auriculata

Also known as Eared watermoss, Butterfly moss, Salvinia auriculata complex, African payal

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Prohibited. Listed as a US federal noxious weed. Illegal to sell, buy, or transport across state lines in the United States. Never release into the wild.

Butterfly fern (Salvinia auriculata) — Mateus Hidalgo · CC BY-SA 2.5 br

Care at a glance

Light: Medium light
CO2: No CO₂ needed
Temperature: 68–82°F; 20–28°C
Max height: 1.6 in; 4 cm

Growth rate: Fast
Placement: Floating
Type: Floating
pH: 6.0–8.0
Hardness: 2–18 dGH
Spread: 11.8 in (30 cm)
Nutrient uptake: Water column
Growth region: Submersed or emersed
Difficulty: Easy
Family: Salviniaceae
Origin: A floating fern from the still fresh waters of tropical Central and South America, where it drifts in green mats across ponds and slow rivers.

Overview

Float it in moderate light and it spreads fast, pulling excess nitrate and phosphate from the water with no CO2 needed. Thin it regularly so it does not shade out plants below or choke gas exchange at the surface. Keep it away from strong surface flow, which flips and tears the leaves.

In the wild

Salvinia auriculata floats as pairs of rounded leaves that sit like tiny butterfly wings on the surface. The leaves are covered in water repellent hairs that keep them dry and give the mat a silvery sheen when splashed. It grows quickly and offers shade and cover for surface dwelling fish and fry.

Good to know

Salvinia is a floating fern with two rounded floating leaves and a third finely divided leaf that hangs underwater and works like a root. It has no true roots and spreads by spores and by fragments breaking off the stem.

Did you know

Several Salvinia species, including members of the auriculata complex, are regulated as noxious weeds in the United States, so keep it contained and never release it into the wild.