Biomedical research relies more and more on the use of vertebrate in vivo models to address questions of biological and medical relevance. The mouse is in this respect certainly the most relevant organism, but in the last 20 years the small, tropical zebrafish (Danio rerio) has gained enormous popularity as an alternative vertebrate system. World‐wide, zebrafish often enable researchers to address specific questions quicker and cheaper than possible in the mouse. Currently, there are more than 700 laboratories using zebrafish, and particular in Europe there is a strong scientific zebrafish community in excess of 300 laboratories. Part of the success of the zebrafish certainly stems from following the ‘3Rs’ principle: research using zebrafish reduces the number of experimental mammalian animals (in particular mice), and derivation of embryos is non‐invasive in contrast to other vertebrate model species. Also,  it has become clear by now that many disease mechanisms relevant to humans can be quickly resolved in zebrafish, and zebrafish research has both helped to identify human disease genes, as well as generating clinically relevant information.

A tank system to house zebrafish in a research facility

For the scientists, fish eggs have little to do with eating caviar. Embryos of the zebrafish and early developmental stages are transparent, which is perfect for the observation of the whole organism with the help of new microscopic methods.

The similarities between zebrafish and humans in respect to their genetic background and organ functions are perfect to find new drugs for the treatment of diseases. The screening for new therapeutic reagents is done with the help of high throughput systems that connect microscopy with automated image analysis, developed by the screening center.