Neon Tetra
Published
Few aquarium fish are as recognisable as the neon tetra. A school of them, each with an electric-blue line along the side and a red stripe below it, is one of the classic sights of the hobby.
Where neon tetras come from
In the wild, neon tetras live in the slow, warm streams of the upper Amazon basin, many of them blackwater or clearwater streams: soft, acidic water, often stained brown by fallen leaves and shaded by forest. The fish was introduced to the aquarium hobby in the 1930s and named after William T. Innes, an American aquarium author. Almost all neon tetras sold today are bred on fish farms, mostly in Asia, rather than caught wild.
The glowing stripe
The blue line is not a pigment. It comes from layers of tiny reflective crystals in the skin that bounce light back, and the fish can change their spacing to shift the shade. At night, or when a neon tetra is stressed, the colours fade; they return once it is calm and the lights are on. Breeders have selected several colour forms, among them gold, diamond (with a shimmering body) and long-finned neons.
A schooling fish
Neon tetras are happiest in a group: a school of six is the minimum, and ten or more brings out their natural behaviour as they turn and move together. Kept alone or in pairs they are timid and hide. They are peaceful and very small, so their tank mates must be gentle too — anything big enough to fit a neon in its mouth will eventually try.
Keeping neon tetras
They prefer soft, slightly acidic water, a planted tank with darker areas and subdued light, and stable conditions; they do poorly in a newly set-up tank that has not finished cycling. Farm-bred fish adapt to a wider range of water than their wild cousins. Neon tetras are difficult to breed at home: they scatter their eggs, which need very soft, acidic water and darkness to hatch.