Public aquariums house billions of aquatic animals. Their welfare, long overlooked, is increasingly subject to scientific scrutiny and institutional improvement.
Aquarium welfare is a frontier area where the philosophical expansion of welfare consideration to fish and invertebrates intersects with practical display requirements. Large pelagic species — great white sharks, whale sharks, oceanic manta rays — have historically had very poor survival in captivity because their spatial and physiological needs cannot be met in any enclosed system. Responsible aquariums have largely stopped attempting to display these species. For the majority of displayed fish species, welfare is primarily determined by water quality, exhibit space and complexity, appropriate social grouping, and species-appropriate diet. The connection between aquarium education and ocean conservation support is well-established, providing a strong rationale for maintaining aquarium programs while continuously improving welfare standards for all displayed species.