Aquariums and marine parks house millions of aquatic animals — welfare standards for fish, rays, sharks, and invertebrates are less developed than for mammals.
Aquatic zoo welfare encompasses the full range of species from small reef fish to large sharks and rays, each with distinct welfare needs that challenge single institutional standards. Large pelagic sharks in tanks cannot perform their natural ranging behavior and show stereotypic circling. Rays in touch tanks experience repeated handling stress. Yet aquariums also provide genuine educational value and house animals rescued from the wild that cannot be returned. Progressive aquariums that invest in species-specific enrichment, welfare monitoring, and honest assessment of which species they can genuinely accommodate provide a model for the sector. The welfare case for keeping large pelagic species in tanks requires honest scrutiny.