Fish used in laboratory research experience pain and stress, yet welfare standards for fish in research settings remain far less developed than for mammals.
Fish welfare in research settings suffers from a persistent cultural assumption that fish do not feel pain in any meaningful way. Scientific evidence now strongly contradicts this assumption: fish show physiological and behavioral responses to noxious stimuli consistent with pain experience. Yet research fish routinely undergo procedures without anesthesia, are housed in barren tanks without enrichment, and are subjected to water quality conditions that cause chronic stress. Bringing fish welfare standards in research up to the level applied to mammals would require significant changes in practice but would substantially reduce suffering in one of the largest groups of research animals by number.