tetra

Tetra
Black neon tetra, Hyphessobrycon herbertaxelrodi
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Characiformes
Family:	-Alestiidae -Characidae -Lebiasinidae
Genera
More than 150[1] karan[clarification needed]

Look up tetra in Wiktionary, the free dictionary.

Pristella tetra — Pristella maxillaris.

Golden Pristella tetra, a morph of Pristella maxillaris.

Silvertip tetra — Hasemania nana.

Tetra are species of small freshwater fish from Africa, Central America and South America belonging to the biological family Characidae and to its former subfamilies Alestiidae (the "African tetras") and Lebiasinidae. The Characidae are distinguished from other fish by the presence of a small adipose fin between the dorsal fin and caudal fin. 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.

The term tetra is not actually a taxonomic, phylogenetic term. Because of the popularity of tetras in the fishkeeping hobby, many unrelated fish are commonly known as tetras, including species from differing families. Even fish that are vastly different may be called tetras. For example, payara (Hydrolycus scomberoides) is occasionally known as the "sabretooth tetra" or "vampire tetra".

Although the list below is sorted by common name, in a number of cases the common name is applied to different species. Since the aquarium trade may use a different name for the same species, advanced aquarists tend to use scientific names for the less-common tetras. The list below is incomplete.

Tetra species: A–D