Zebrafish and other fish used in scientific research are subject to laboratory animal welfare regulations in some jurisdictions, with evidence for their sentience increasing ethical obligations.
Laboratory fish welfare occupies an unusual position: zebrafish are among the most scientifically studied vertebrates but receive far less welfare consideration than mammals in equivalent research contexts. Their inclusion in EU and UK animal protection legislation represents scientific recognition of their sentience status, creating legal obligations for pain management, environmental enrichment, and minimization of animal numbers. The welfare implications of zebrafish research are significant — millions of animals annually — and relatively modest improvements in standard housing and procedure protocols could produce substantial aggregate welfare gains. The 3Rs framework applied consistently to fish research — asking whether alternatives exist, whether animal numbers can be reduced, and whether suffering can be refined — provides a practical welfare improvement pathway within existing research paradigms.