Fish cognitive abilities — including tool use, social learning, and individual recognition — are more sophisticated than previously assumed, with direct welfare implications.
Fish cognition research has systematically revised estimates of fish intelligence upward: social learning, memory, individual recognition, and possible self-awareness demonstrate a richness of inner life inconsistent with treating fish as simple reflex machines. The welfare implications are direct: an animal capable of social learning and individual recognition has a more complex social world that is damaged by isolation; an animal capable of forming spatial memories has cognitive needs that barren tank environments cannot meet. The welfare bar for fish must be raised to match their demonstrated capabilities.