Zebrafish have become one of the most important research model species globally. Their welfare needs are less understood than mammalian models but are increasingly researched.
Zebrafish welfare represents a growth area in welfare science driven by the rapid expansion of their use in research. Because they are fish, they are sometimes dismissed as having less welfare significance than mammals — an assumption that is increasingly challenged by the pain science literature. Zebrafish show nociceptive responses, learned fear, and physiological stress indicators that parallel mammalian responses. Their social nature means that isolation causes measurable stress. Regulatory gaps — particularly the exclusion of embryos and early larvae from welfare oversight — mean that millions of zebrafish develop in conditions that may cause significant suffering without legal protection. As use scales, the welfare investment required to address these gaps grows proportionally.