Fish are increasingly used in biomedical research, and growing evidence of their sentience makes the development of fish-specific welfare standards an urgent priority.
Fish welfare in research settings has historically received far less attention than that of mammals, but the science increasingly supports the view that fish can suffer in morally relevant ways. The sheer numbers used — tens of millions annually — make improvements to fish welfare potentially one of the highest-impact areas of laboratory animal welfare reform. Priority areas include better water quality monitoring, anesthesia protocols for procedures, reduced stocking densities, and more careful consideration of the developmental stages at which larvae become welfare-relevant. The 3Rs framework (Replace, Reduce, Refine) is increasingly being applied to fish research.