Zebrafish are increasingly used in biomedical research, and their welfare needs in laboratory settings are beginning to receive systematic attention.
Zebrafish occupy an unusual regulatory position in many countries: they are vertebrates with documented pain responses but are often excluded from the welfare protections that apply to mammals and birds. Research on zebrafish welfare has accelerated alongside their increasing use, establishing that tank density, water quality, and environmental enrichment significantly affect welfare indicators. Applying the 3Rs framework rigorously to zebrafish research — reducing numbers, refining procedures, and replacing with non-sentient alternatives where possible — is as morally obligatory as for any other research vertebrate.