X-ray Tetra

A hardy, near-transparent tetra with black and yellow marks on its fins, and one of the very best first fish. A pale-finned strain is also sold.

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 eat baby shrimp.

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

An undemanding X-ray tetra that eats flake, micro pellets and small frozen foods, picking food from midwater.

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.