Scientific understanding of fish cognition has advanced dramatically in the last decade, with implications for how fish welfare is evaluated and what standards are appropriate for fishing, farming, and research.
The cognitive complexity of fish was systematically underestimated for decades, partly because fish do not express pain in ways humans easily recognize. Advances in fish cognition research have consistently demonstrated greater sophistication than assumed — social intelligence, learning, tool use, and self-recognition capabilities that challenge simple dismissals of fish sentience. The welfare implications are significant: if fish experience pain, fear, and stress, the scale of suffering involved in commercial fishing, aquaculture, and research is enormous. The precautionary principle supports applying welfare protections proportionate to the growing evidence.