Tetras are members of the Characidae family and can be recognized by the adipose fin, a small rounded fin between the dorsal fin and tail. These fish have several bones that join the inner ear and swim bladder, which enhances the hearing of these colorful fish. Tetras are found primarily in the streams and rivers of South America and Africa. Most tetras are active schooling fish that work well in the peaceful community aquarium. It is ideal to keep six or more fish of the same species in the aquarium. Many different schools of tetras can be maintained in the aquarium providing a unique display of color. Tetras do best in a well-planted aquarium with moderate lighting. Species such as the neon tetra and cardinal tetra are among the most popular of all freshwater fish, adding a touch of brilliance and social interaction to the community aquarium.