Marine invertebrates kept in aquariums present challenging welfare questions. While their sentience is uncertain, best practice in husbandry applies precautionary principles to minimize potential suffering.
Invertebrate welfare in aquariums sits at the outer boundary of welfare consideration - the sentience evidence is weak for most groups, yet the precautionary principle suggests thoughtful husbandry. The clearer welfare concern is the mortality associated with wild collection and transport - even if individual invertebrates lack subjective experience, the ecological harm and resource waste of high transport mortality is a legitimate concern. Welfare-conscious reef keeping involves sourcing captive-propagated animals where possible, maintaining optimal water parameters, and monitoring for stress indicators like retracted polyps, color changes, or tissue necrosis.