Environmental enrichment for captive fish significantly improves welfare outcomes, with benefits for both individual wellbeing and the validity of biomedical research.
Fish enrichment is an area where the welfare and scientific arguments are aligned: enriched fish are better welfare subjects and better experimental models simultaneously. The historical assumption that fish in tanks do not require environmental complexity is giving way to evidence-based recognition that fish have sophisticated environmental preferences and suffer from barren housing. The practical costs of fish enrichment are low relative to the welfare and scientific benefits, making this one of the most accessible welfare improvements available to laboratories and aquaria. The challenge is cultural change among researchers and display professionals who may not have been trained in fish welfare science.