The zebrafish (Danio rerio) is a model organism in scientific research.
The zebrafish gets its name, as well as its nickname 'pyjama fish', from its white and steel blue horizontal stripes. It measures from 2 to 5 centimetres in length and prefers to live in water at temperatures around 21°C, even though it can survive in water from 5 to 30°C. It can live for 2 to 3 years, with a generation time of 3 to 4 months.
A female adult zebrafish. © C. Thisse