Zebrafish are now the second most widely used vertebrate in biomedical research. Their social nature and shoaling behavior are critical welfare considerations that affect both animal wellbeing and experimental validity.
Zebrafish welfare has historically received less attention than mammalian research subjects, but the science now clearly supports their capacity for chronic stress and the importance of social housing. Isolated zebrafish show behavioral and physiological indicators of distress that compromise both their welfare and the quality of research data. Institutions that prioritize shoaling - providing appropriately sized groups in adequately sized tanks with environmental enrichment - achieve better welfare outcomes and more reliable experimental results.