Definition of tetra in English:



  • A small tropical freshwater fish that is typically brightly colored. Native to Africa and America, many tetras are popular in aquariums.

    • ‘Like many tetras, the glowlight tetra is a schooling fish and prefers to swim in the company of at least seven of its peers.’
    • ‘Cardinal tetra is the bright glowing variety and marble molly looks like dotted marble and comes both in white and black.’
    • ‘On a recent visit, my friend I and were seated in the back corner, next to a large aquarium whose only occupants seemed to be a pair of tetras and some dazed-looking goldfish.’
    • ‘So there was nemo, many types of guppies, tetra and this queer tortoise with a spout for mouth - really strange looking.’
    • ‘The tetra is particularly popular with hobbyists, since it is attractive in appearance, undemanding in maintenance, and easily bred.’
    • ‘It was a black skirt tetra, which is a fairly common aquarium fish.’
    • ‘Pachon Cave in northeastern Mexico supports a population of blind Mexican tetras isolated from base-level populations by elevation.’
    • ‘Another member of the large characin clan, the lemon tetra has a fairly elongated body like its smaller relative the neon tetra and like neons and other characins, the lemon tetra does best if kept in small schools of six to eight fish.’
    • ‘The Mexican tetra is easy to raise in the laboratory and exhibits many of the attributes that have made zebrafish a popular model system in developmental biology.’
    • ‘Rosy and rummy-nosed tetras and uaru cichlids swam en masse.’
    • ‘The freshwater mollies and tetras are rather ferocious and may take chunks out of your skin like miniature piranhas.’
    • ‘We have a freshwater fish tank community of tetras, catfish, gouramis and loaches.’


Mid 20th century: abbreviation of modern Latin Tetragonopterus (former genus name), literally ‘tetragonal finned’.