The science of fish pain and sentience has advanced substantially, with implications for how fish are treated in aquaculture, recreational fishing, and research contexts.
The recognition of fish as likely sentient beings capable of experiencing pain has had profound welfare implications for an enormous number of animals. Fish are the most numerally abundant vertebrates in human use - trillions are caught, farmed, and killed annually. If fish experience pain, the scale of potential suffering involved dwarfs most other animal welfare concerns. The science has progressively strengthened: fish have the neurological machinery for nociception, respond behaviorally and physiologically to painful stimuli, and respond to analgesics - the key criteria for inferring pain experience in other animals. Welfare standards are beginning to catch up, but the gap between current treatment of fish and evidence-based welfare provision remains vast.