Black Skirt Tetra
Gymnocorymbus ternetzi
Beastly Facts · Updated
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Overview
The black skirt tetra is a hardy, deep-bodied schooling fish from the Rio Paraguay basin in South America, also sold as the black widow tetra. It eats almost anything and handles a wide range of water, but it nips fins, so it is kept in a school of 12 and away from slow, long-finned fish. The white skirt and long-fin forms are the same species, and so are fluorescent GloFish Skirt Tetras.
Quick Facts
Native Range
Rio Paraguay and Guaporé basins (Brazil, Bolivia, Argentina)
Natural Habitat
Small, slow-moving creeks and streams under dense overhanging vegetation, and plant beds in floodplain oxbow lakes
Adult Size
About 2-2.5 inches (5-6 cm) in aquariums; up to 3 inches (7.5 cm)
Wild Diet
Worms, small crustaceans and insects
Wild Lifespan
Not documented in the wild; about 3-5 years in captivity
Conservation Status
Least Concern (IUCN)
History
George Albert Boulenger described the species in 1895 as Tetragonopterus ternetzi, from fish collected at Descalvados in Mato Grosso, Brazil, and named it for the Swiss-born naturalist Carl Ternetz, who assembled the collection. Carl Eigenmann moved it into the genus Gymnocorymbus in 1910. A relative in the same genus, Gymnocorymbus bondi, honors Frank Bond, father of the ornithologist James Bond, whose name Ian Fleming borrowed for his spy.
Compare
Black Skirt Tetra
Human
Adult Size
About 2-2.5 inches (5-6 cm) in aquariums; up to 3 inches (7.5 cm)
5-6 feet (150-185 cm); ~135-200 lbs
Wild Lifespan
Not documented in the wild; about 3-5 years in captivity
~73 years (global average)
Wild Diet
Worms, small crustaceans and insects
Omnivorous - eats just about anything
Native Range
Rio Paraguay and Guaporé basins (Brazil, Bolivia, Argentina)
Global - originated in Africa roughly 300,000 years ago
Natural Habitat
Small, slow-moving creeks and streams under dense overhanging vegetation, and plant beds in floodplain oxbow lakes
Everywhere from arctic tundra to tropical megacities
Conservation Status
Least Concern (IUCN)
Least Concern (8+ billion and counting)
Test Yourself
What's the Black Skirt Tetra's native range?
Care Guide
Black Skirt Tetra Care Guide
The hardy, black-finned schooler that keeps its nipping in the family!
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Deep Dive
Health and More
Did You Know?
Every black skirt tetra starts out with ovaries: in fish that become males, the egg tissue breaks down and is replaced as the testes develop.
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