Fish
Tetra
Characidae · also called tetras
Say tetra and most people picture a tiny, glowing neon fish darting through a home aquarium in a tight, colourful school. That image is accurate for plenty of species, but it covers only a fraction of a genuinely enormous family that also includes the piranha, a fish whose reputation could not be further from peaceful and colourful.
Overview
The tetra, family Characidae, is one of the largest freshwater fish families in the world, found across Central and South America and parts of Africa. Most species are small, schooling omnivores, though the family’s diversity spans an extraordinary range of size and temperament.
One family, two reputations
The gentle, brightly coloured aquarium tetra and the powerfully toothed piranha sit in the very same family, a reminder that a common name built around one famous member can obscure just how much variation an enormous, successful fish lineage actually contains.
Status
Least Concern collectively — common and widespread across Central and South American freshwater habitat, though some individual species with narrower ranges face localised pressure.
Tetra: common questions
Are piranhas actually tetras?
Yes, piranhas belong to the same very large family, Characidae, as the tetra, a family that spans an enormous range of size, behaviour, and temperament, from tiny, peaceful, brightly coloured aquarium species like the neon tetra to considerably larger, powerfully toothed predatory species such as piranhas, all grouped together under the same broad family classification.
Why are tetras so popular in home aquariums?
Many tetra species, most famously the neon tetra, are popular in home aquariums because they are small, brightly coloured, generally peaceful toward other fish, form attractive schools, and have relatively straightforward care requirements, a combination that has made them a long-standing staple among both beginner and experienced aquarium keepers.
How many different kinds of tetra are there?
The tetra family, Characidae, contains many hundreds of described species, making it one of the largest and most diverse freshwater fish families in the world, with considerable variation in size, colouration, diet, and behaviour across that diversity, meaning the term tetra actually covers a far broader range of fish than its popular aquarium reputation might suggest.
Where are tetras found in the wild?
Tetra species are found across a wide range of freshwater habitats in Central and South America, including rivers, streams, and seasonally flooded forest, with a smaller number of related species also found in African freshwater systems, reflecting the considerable geographic spread of this very large fish family.