TankBud

Water spangles

Salvinia minima

Also known as Common salvinia, Floating fern, Water fern

FreshwaterFloatingRhizome divisionSide shoots

Invasive. A fast-spreading floating fern that is regulated as a noxious weed in some states (e.g. Texas). Never release into the wild; dispose of in the trash.

Water spangles (Salvinia minima)
Krzysztof Ziarnek, Kenraiz · CC BY-SA 4.0

Care at a glance

Light
Medium light
CO2
No CO₂ needed
Temperature
64–82°F
18–28°C
Max height
1.2 in
3 cm
Growth rate
Fast
Placement
Floating
Type
Floating
pH
6.0–8.0
Hardness
2–20 dGH
Spread
1.6 in (4 cm)
Nutrient uptake
Water column
Growth region
Submersed or emersed
Difficulty
Easy
Family
Salviniaceae
Origin
South America, Mesoamerica and the West Indies

Overview

Water spangles is a small floating fern for a calm water surface, easy and undemanding to keep.

Did you know

The tiny four-pronged hairs on its leaves trap a layer of air that makes water spangles nearly impossible to wet. The same trick on its giant relative inspired engineers studying drag-reducing, self-drying surfaces.

Caring for water spangles

Scatter water spangles on still water and keep filter agitation low. Heavy spray and surface flow make it rot or sink.

It grows in medium light with no CO2. It takes its food straight from the water, so feed the tank with a liquid fertilizer rather than root tabs. It handles 64 to 82°F (18 to 28°C).

Water spangles multiplies quickly as it breaks apart and buds off new plants, and the mat shades the tank below. Skim out the excess regularly. Never release it, and put all trimmings in the trash.

Good to know

Water spangles, Salvinia minima, is a true fern in the family Salviniaceae and the order Salviniales. It reproduces by spores and fragmentation rather than flowers or seeds, and most aquarium-grown plants are sterile. Its oval leaves, about half a centimeter to two centimeters across, float in pairs. A third, finely divided leaf hangs below and takes the place of true roots. The leaf hairs branch into four points that do not meet at the tips, which tells it apart from the much more dangerous giant salvinia.

In the wild

Water spangles is native to South America, Mesoamerica and the West Indies, where it floats on still ponds, ditches and slow streams. It was introduced to the southern United States in the 1920s and 1930s and has spread widely there, forming dense surface mats. It is now a recognized invasive species, listed as a prohibited noxious plant in Texas and regulated in several other states.

Common questions

Does water spangles need to be planted in the substrate?

No. Water spangles floats at the surface and takes its nutrients straight from the water.

Does water spangles need CO2?

No. Water spangles grows well without added CO2.

How much light does water spangles need?

Water spangles wants medium light. A light sold for planted tanks covers it.

How do you propagate water spangles?

Water spangles propagates by rhizome division and side shoots. Cut the rhizome into pieces with several leaves each, then tie or plant each piece. Side shoots bud off and float free.

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