Scientific consensus on fish pain has shifted dramatically over the past two decades. Evidence now strongly supports that fish experience pain, with practical implications for fishing, aquaculture, and research.
Recognition of fish pain has profound implications for how we manage the largest-scale killing of any animal group. The behavioural and neurological evidence for fish nociception is now robust: fish show avoidance learning after noxious stimulation, protective guarding of injured areas, and analgesic-reversible behaviour changes — the key lines of evidence used to infer pain in mammals. Whether fish have subjective painful experience remains philosophically uncertain, but the precautionary principle demands welfare consideration given the weight of evidence and the enormous numbers involved. Practical implications range from fishing method reform — percussion stunning before gill cutting, ice slurry limitations, and live chilling minimisation — to aquaculture slaughter improvements and research refinement. The fish welfare field is young but growing rapidly; regulatory frameworks in Norway, the UK, and EU are incorporating fish welfare requirements at a pace not seen in other aquatic species.