Scientific evidence for pain and distress in fish has grown substantially, challenging assumptions that fish do not suffer and informing debates about angling, farming, and bycatch welfare.
The scientific consensus on fish pain has shifted dramatically over the past two decades. Early dismissals of fish pain capacity based on the absence of a neocortex have been revised — pain processing may not require the same neural structures as in mammals, and behavioural evidence of suffering in fish is compelling. Fish avoid aversive stimuli, show cognitive responses to pain that suggest more than simple reflexes, and have pain relief systems that respond to analgesics. This evidence has welfare implications across the entire spectrum of human use of fish — from aquaculture to recreational angling to bycatch — affecting millions of individual animals.