Zebrafish are increasingly used in biomedical research. Their welfare needs are specific and increasingly addressed through evidence-based refinement of husbandry and experimental protocols.
Zebrafish welfare is a rapidly developing area driven by their increasing importance as a model organism and growing recognition of their sentience. Early use of zebrafish was accompanied by assumptions that their small size and phylogenetic distance from mammals meant welfare considerations were minimal. Evidence now shows zebrafish show pain avoidance, social stress responses and individual personality differences that indicate morally relevant experiences. Refinements including group housing, environmental enrichment, appropriate water quality management and anaesthesia for painful procedures significantly improve zebrafish welfare at modest implementation cost. Applying Three Rs principles rigorously to zebrafish use reflects both scientific ethics and institutional welfare commitments.