Scientific advances in fish cognition have fundamentally changed our understanding of fish as sentient animals deserving welfare consideration.
Fish cognition research has transformed the scientific and ethical landscape for fish welfare. The historical dismissal of fish as simple reflex machines has been comprehensively overturned by evidence of sophisticated learning, social awareness, and physiological pain processing. This evidence base now supports the conclusion that fish can suffer and that their welfare deserves serious consideration. The welfare implications are enormous given the scale of fisheries and aquaculture — hundreds of billions of fish annually. Transitioning from a default assumption of fish insensience to a precautionary approach that minimizes fish suffering requires both policy change and consumer awareness.