The science of fish pain has advanced significantly in recent decades, with growing consensus that fish have the neural architecture for pain experience and the welfare implications this entails.
The scientific case for fish pain has shifted from contested to broadly accepted among researchers: fish have the nociceptive systems, brain structures activated by noxious stimuli, and behavioural responses consistent with pain experience. Legal protection has not kept pace with scientific consensus — most fish remain unprotected by welfare legislation in most jurisdictions. The welfare implications are enormous: hundreds of billions of fish are killed annually in conditions that would be unacceptable if they were mammals.