Zebra Danio: The Aquarium Fish That Became a Lab Icon

In this guide

Overview

The zebra danio, Danio rerio, is a small, energetic fish with horizontal blue and silver stripes, native to slow-moving streams and rice paddies across the Ganges and Brahmaputra river basins of India, Pakistan, Bangladesh, Nepal and Bhutan, with the species first formally described from the Kosi River in northern India. This is one of the few popular aquarium fish that is genuinely native to India rather than imported from South America or elsewhere in Asia. Older references also list Myanmar as part of its range, but current research considers those records likely to be a related, separately described species rather than the true zebra danio.

Beyond the aquarium trade, zebrafish, as scientists call it, is one of the most important model organisms in modern biomedical research, used worldwide to study genetics, development and disease, precisely because its embryos develop quickly and transparently outside the mother's body. It was also the basis of the first genetically modified pet fish sold commercially, the fluorescent GloFish.

Tank and water requirements

A group of six or more zebra danios does well in a tank of sixty litres or larger, ideally with plenty of length for swimming, since this is a fast, active fish that appreciates open water. They are extremely hardy and tolerate a wide range of Indian water conditions and temperatures without much fuss.

A tight-fitting lid is worth having, since zebra danios are enthusiastic jumpers, especially in a tank without much surface cover.

Diet and behaviour

An easy omnivorous diet of flakes, micro pellets and occasional live or frozen food suits them well. They are fast, constantly active swimmers that do best with similarly energetic tankmates rather than slow, docile fish that might feel harassed by the pace.

Their hardiness and tolerance of a wide temperature range make them one of the best choices for a beginner's first tank, including one still being cycled, since they handle imperfect water conditions better than most tropical fish.

Buying tips

• Among the cheapest fish available in India, often ten to twenty five rupees per fish
• GloFish varieties, genetically modified for fluorescent colour, are increasingly available through specialist importers, though standard zebra danios remain far more common
• A genuinely good starter fish given their hardiness, low cost, and tolerance for a tank still settling in

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