Zebrafish (Danio rerio) have become a major model organism in biomedical research. Their welfare requires attention to water quality, group housing, enrichment, and humane endpoints.
Zebrafish welfare has received increasing attention as their use in research has grown dramatically. As vertebrates capable of experiencing pain, they are subject to welfare regulation in the EU and increasingly elsewhere. Key welfare considerations include water quality management, appropriate social housing, enrichment through substrate and plant structures, and humane endpoints that prevent prolonged suffering in experimental disease models. The large number of zebrafish used in research — far exceeding mammalian species — means that even small improvements in individual welfare protocols have significant aggregate impact.