Black Widow Tetra (Gymnocorymbus sp.) – 3cm

The Black Widow Tetra is an active, fast-moving species is a great choice for aquarium beginners.  They don’t require a large tank, 45 litres or more, and are relatively small at 6 cm adult size.

Hardy and easy to care for, the Black Widow Tetra (Gymnocorymbus ternetzi), also known as black skirt tetra is a schooling fish that, contrary to its name, comes in several colors. While the wild black widow tetra is dark in color, consider the many-colored varieties that have been captive-bred.

They come from the Rio Paraguay and Guaporé basins in Brazil, Bolivia and Argentina.

Behaviour

A schooling fish by nature, black widow tetras are best kept in groups of six or more to create a healthy, happy school of fish, but avoid housing them with smaller species (particularly those with long, flowing fins) as black widows do sometimes nip.

Tank Conditions

Black widows are an undemanding species that adapt to a range of conditions, though subdued lighting and neutral-colored gravel substrates are preferred. They are accustomed to large plants in their natural habitat and enjoy a well-planted aquarium with some open swimming space.

Compatibility

They make an excellent community fish due to their peaceful nature. Some owners report that they sometimes nip the fins of slower-moving fish, particularly those with long, flowing fins such as bettas or angelfish.

Feeding

Black widow tetras readily accept virtually any food, including live, fresh, frozen, freeze-dried, or flake foods. For the breed’s optimal health, provide a variety of foods, which can include high-quality flake foods, brine shrimp, and any type of worms, as well as vegetable supplements and spirulina.

Care

In addition to the usual Ick, Black Skirt Tetras are at risk for fungal and bacterial infections. The most common are Dropsy, fin rot, and Fish Fungus. Most of these issues can be treated by improving water quality and using over-the-counter medications.

See Fish Disease Diagnosis and Treatment at Rebel Pets for help with diagnosing and treating diseases.