25 Zebrafish Facts: The Tiny Striped Fish That Helps Science

The zebrafish's scientific name is Danio rerio.

Zebrafish belong to the carp and minnow group of fish.

Zebrafish are native to South Asia, including India, Bangladesh and Nepal, especially around the Ganges and Brahmaputra river basins.

The zebrafish was first described by scientists in 1822, from fish found in Bengal.

Adult zebrafish are usually only about 3 to 4 centimetres long.

They get their name from the dark blue horizontal stripes running along their silvery-gold bodies.

In the wild, zebrafish live in slow-moving streams, ponds and even flooded rice fields.

Zebrafish swim together in groups called shoals.

They are omnivores, eating tiny insects, plankton, worms and algae.

You can watch a zebrafish grow inside its egg

Zebrafish eggs and embryos are almost completely transparent, so scientists can watch every stage of development through a simple microscope. Within about 24 hours of fertilisation, the tiny embryo's heart begins to beat, and its eyes, brain and spine start to form. Baby zebrafish usually hatch after just two to three days. Being able to watch a living animal build its organs in real time has made zebrafish one of the most useful animals in biology.

A female zebrafish can lay hundreds of eggs at a time, and can breed every week or so.

Male zebrafish are usually slimmer and more golden, while females have rounder, whiter bellies.

Zebrafish have 25 pairs of chromosomes.

Scientists finished reading the zebrafish's full genetic code in 2013.

About 70% of human genes have a matching version in zebrafish, and over 80% of genes linked to human diseases have a zebrafish counterpart.

Because of this, zebrafish are used in thousands of laboratories worldwide to study diseases such as cancer, heart disease and muscle disorders.

Zebrafish are also used to test new medicines and check whether chemicals are harmful.

The American scientist George Streisinger helped make zebrafish popular in research in the 1970s and 1980s, and he is often called the father of zebrafish research.

Scientists have bred a special see-through adult zebrafish called "casper", which lets them watch organs and even tumours inside a living fish.

Zebrafish can regrow parts of their heart

Unlike humans, zebrafish have an amazing ability to heal. If part of a zebrafish's heart is damaged, it can regrow the lost heart muscle within a couple of months, without leaving a scar. Zebrafish can also regrow their fins, parts of their spinal cord and even cells in the backs of their eyes. Scientists are studying how they do it in the hope that one day it could help people recover from heart attacks and other injuries.

The glowing pet fish sold as "GloFish" were originally made from zebrafish, given glowing genes from jellyfish and corals.

Scientists have even studied zebrafish in space, to learn how weightlessness affects living things.

Zebrafish are hardy, easy to care for and popular in home aquariums, where they are often called zebra danios.

Scientists use zebrafish to study how animals sleep, learn and even form memories.

Zebrafish usually live for around three to five years in aquariums.