Fish demonstrate learning, memory, social cognition, and behavioral flexibility that support a welfare-significant inner life, challenging traditional assumptions about fish experience.
The scientific understanding of fish cognition and welfare has transformed dramatically over the past two decades. Fish are no longer plausibly characterized as simple reflex machines incapable of morally significant experience. The evidence for nociception, pain behavior, stress responses, learning, memory, and social cognition meets or exceeds the standards applied to establish these capacities in other vertebrates. This has profound implications for the welfare significance of how fish are treated in fisheries, aquaculture, sport fishing, the ornamental trade, and research, given the billions of fish affected by each of these industries.