Zebrafish are increasingly used in biomedical research as an intermediate model between cell culture and mammals, with welfare considerations that differ from terrestrial research animals.
Zebrafish welfare science is evolving rapidly alongside their expanding use in research. Adult zebrafish are protected under research animal welfare legislation in the EU and UK, reflecting evidence of pain sensitivity and social needs. However, larvae used extensively in high-throughput screens are currently unprotected despite evidence of developing nociceptive systems. Water quality management, appropriate stocking density, and social grouping are fundamental to zebrafish welfare in laboratory settings.