Zebrafish are increasingly used in biomedical research, raising welfare questions about their capacity for pain and stress.
The rapid expansion of zebrafish use in biomedical research has outpaced development of welfare standards appropriate to their capacity for pain and stress. Behavioral evidence including avoidance learning, conditioned place aversion, and analgesic-responsive responses to noxious stimuli suggests that adult zebrafish experience something analogous to pain. Yet welfare protections in many jurisdictions apply less rigorously to zebrafish than to mammals. Applying the 3Rs — replacement, reduction, and refinement — to zebrafish research would reduce unnecessary suffering while maintaining scientific value.