Research over the past two decades has transformed our understanding of fish cognition, revealing capacities that have important implications for their welfare.
Fish were long dismissed as simple automatons driven by instinct, but research has revealed complex cognitive abilities including tool use, social learning, individual recognition, and numerical discrimination. These findings do not prove fish are conscious but significantly raise the plausibility that they have welfare-relevant experiences. The legal and regulatory treatment of fish as essentially feelingless creates a large discrepancy between scientific evidence and policy, with significant welfare consequences for billions of fish.