The Black Tetra (Gymnocorymbus ternetzi) also known as the black skirt tetra, high-fin black skirt tetra, and black widow tetra, is a freshwater fish of the characin family (Characidae). It is native to the Paraguay and Guaporé River basins of southern Brazil, Argentina, and Bolivia.
Growing to about 6 cm (2.5 in) total length, the black tetra has a roughly tetragonal body shape and is greyish in colour, fading from light at the nose to near black at the tail. Two prominent black vertical bars appear just posterior of the gills. It is a schooling fish, and requires at least six in a group.
The black tetra is an omnivore and will eat most anything it can fit into its mouth. Care should be taken that all members of the school receive adequate food. Food items that are too large will be rejected by the fish. Keepers may provide live foods such as daphnia and mosquito larvae, and frozen foods like bloodworms.
