Black Skirt Tetra

Gymnocorymbus ternetzi

The black skirt tetra (Gymnocorymbus ternetzi), also called the black widow tetra in some aquarium circles, is a deep-bodied characin from slow rivers and floodplain waters of southern South America. Wild-type fish have a silvery body, dark vertical bars near the front half, and broad black dorsal and anal fins that create the skirt-like outline. Selective breeding has produced long-fin, white, and other domestic strains, but the natural form remains a hardy schooling aquarium fish.

Black skirt tetras are best kept in groups, where their chasing and fin-nipping tendencies are spread among their own kind instead of focused on slow tankmates. They suit planted community aquaria with stable filtration, open swimming room, and moderate water movement. A varied diet of quality flakes, small pellets, frozen foods, and occasional live foods keeps them in good condition. Buyers should avoid dyed or damaged fish and choose active individuals with clear eyes, full fins, and no pinched bodies.