The question of whether fish feel pain has profound implications for billions of animals. A growing body of evidence challenges the long-held assumption that fish are non-sentient, with important welfare implications.
The precautionary principle applies strongly to fish welfare: given substantial evidence of nociception and pain-related behaviour, combined with the vast numbers of fish affected, treating fish welfare as irrelevant carries enormous moral risk. The emerging scientific consensus increasingly supports fish sentience. Welfare-positive practices — humane slaughter, reduced crowding, anaesthesia for procedures — should be adopted now rather than waiting for philosophical certainty about fish consciousness.