# tetra

/ˈtɛtɹə/ (US) · /tˈɛtɹɐ/ (UK) · CEFR C2 · Noun

Source: https://englishreference.com/word/tetra
Updated: 2026-05-30

## Definition

a small, colorful tropical fish that people often keep in home aquariums. They usually live in groups and come from rivers in South America and Africa.

For teachers: any of various small, often brightly colored freshwater fish of the family Characidae, popular in the aquarium trade. Typically refers to species within the genera Paracheirodon or Hyphessobrycon.

## Examples

- I bought five neon tetras for my new fish tank.
- The school of tetras darted through the aquatic plants, their silver scales catching the light from the aquarium lamp.
- While the neon tetra is perhaps the most iconic, many hobbyists prefer the cardinal tetra for its more extensive red coloration and hardiness in established blackwater setups.

## Usage notes

- The plural can be either 'tetra' or 'tetras', though 'tetras' is more common when referring to multiple individuals.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.