Mexican Tetra

Best known in its blind form, which has no eyes and finds its way by sensing movement in the water. The two forms may have split only about 10,000 years ago. It is hardy, peaceful and prefers cooler water.

Check the scientific name when buying, as common names vary between sellers and countries.

Mature females are usually rounder in the belly, and males are usually slimmer and often brighter.

A long tank with open swimming water, plants around the edges and steady filtration suits this fish. A darker substrate and some floating plants usually bring out its colour.

Active and social, and most settled when kept with its own kind.

Keep a group of at least 6, and more if you can. Larger groups are calmer and show better colour and behaviour.

Not territorial, although males may spar and display.

Suits a community of similar-sized, peaceful fish that like the same water. Avoid large predators, which will treat it as food. It may nip the fins of slow or long-finned fish, and a larger group usually reduces this. It is likely to eat shrimp.

Fairly tolerant of different water, if it is clean and stable.

A hardy omnivore that eats almost anything, including plant matter. Feed pellets and flake with frozen foods and some vegetable matter.

Feed small amounts, and remove anything left after a few minutes.

An egg scatterer with no parental care. Adults eat eggs and fry, so use a separate tank with fine plants, moss or mesh on the bottom, and remove the adults after spawning. The fry need very small foods at first.