A tetra is one of several species of small freshwater fish from Africa, Central America, and South America belonging to the biological family Characidae and to its former subfamilies Alestidae (the "African tetras") and Lebiasinidae. The Characidae are distinguished from other fish by the presence of a small adipose finbetween the dorsal and caudal fins. Many of these, such as the neon tetra (Paracheirodon innesi), are brightly colored and easy to keep in captivity. Consequently, they are extremely popular for home aquaria.
Tetra is no longer a taxonomic, phylogenetic term. It is short for Tetragonopterus, a genus name formerly applied to many of these fish, which is Greek for "square-finned" (literally, four-sided-wing).
Tetras are small sizes fish that do well in schools or groups of 4 or more fish. They do require some attention to the water qaulity and vulnerable to more aggresive tank mates. Availible in a large variety to suite eveyones needs.
The Neon Tetra is often described as the jewel of the aquarium hobby. It is easy to see why it is one of the most popular freshwater tropical fish.
With its iridescent blue body and bright red tail, Paracheirodon innesi creates an exciting splash of color in any aquarium, especially when kept in schools of six or more.
At first glance, the Silver Tip Tetra is a fairly dull, grey fish. Nothing to get excited about. However, keep the Silver Tips in large enough numbers and its beauty becomes obvious. A school of Silver Tip Tetras measuring 30, 40, or 50 fish, moving back and forth across the aquarium looks simply stunning.
The Black Neon Tetra has a peaceful nature, very energetic and is an excellent addition to any community aquarium. However, it is advisable not to house them with large, aggressive fish, or they may be outcompeted for food or eaten. These Tetras are a schooling fish and prefer to be in groups of at least six.