Black Tetra, Gymnocorymbus ternetzi

The Black Tetra (Gymnocorymbus ternetzi), known also as the Black Skirt Tetra, High-fin Black Skirt Tetra, and the Black Widow Tetra, is a freshwater fish belonging to the characin family Characidae. It is native to the Paraguay and Guapore River basins of southern Brazil, Argentina, and Bolivia.

Achieving lengths of about 2.5 inches in total length, the Black Tetra has a tetragonal body shape and is greyish in coloration, fading from light at the nose to near black at the tail. Two prominent black colored vertical bars appear just posterior of the gills. It is a schooling fish, and needs at least six in a group.

The Black Widow Tetra feeds on small insects, crustaceans, and worms.

This tetra fish is a common fish that can be readily acquired from aquarium dealers. It will live in warm water but, being native to the Rio Paraguay south of the Tropical of Capricorn, it will also tolerate slightly cooler water than some tropical fish. It can be kept in aquariums that aren’t heated in rooms that do not get cold. Like the majority of tetras, it requires soft water with a pH between 6.5 and 6.8, and plenty of plants.

Although it is not usually aggressive towards others, it has been known to fight with the male Betta splendens. It can also conflict with other individuals of its species, with dominant fish harrying weaker ones.

It is an omnivore and will eat mostly anything that it can fit into its mouth.

It achieves sexual maturity by two years of age. It was spawn in the winter of about 78 degrees Fahrenheit.

Image Caption: Black tetra. Credit: emptyvi/Wikipedia (CC BY-SA 3.0)