Black Tetra (Gymnocorymbus ternetzi), also known as the black skirt tetra, petticoat tetra, high-fin black skirt tetra, and black widow tetra, is a freshwater fish of the Characin family (Characidae) native to Argentina, Brazil and Bolivia. A denizen of small streams and rivers, this species has become a very popular aquarium fish. It grows to about 2 inches and is known to breed readily in captivity. Its eggs hatch within 24 hours, and the young fishes feed on rotifers.1 Black tetras do not take care of their young. Usually they will eat both eggs and young if given a chance.3
The Black Tetra is placid species that travels in schools and inhabits the middle strata of the tank. It is a schooling fish, and requires at least six in a group. IN its natural habitat, it feeds on small crustaceans, insects, and worms. In an aquarium it will it prepared foods and small live foods. This species is hardier than most tetras, but any change in water temperature should still be performed gradually. It requires soft, acidic conditions.