The scientific consensus on fish pain and sentience has strengthened substantially over two decades, with implications for how we manage billions of farmed and wild-caught fish.
The scientific evidence for fish pain has moved from contested to mainstream over the past twenty years. Early scepticism focused on the absence of a neocortex in fish, but subsequent research has identified alternative neural substrates capable of supporting pain processing. The precautionary principle in welfare ethics suggests that uncertainty about sentience should prompt protective behaviour rather than dismissal. Policy has begun to follow the science; the UK Animal Welfare (Sentience) Act 2022 included fish, decapod crustaceans, and cephalopods as sentient animals. Many aquaculture and fishing practices were designed in an era when fish pain was denied, and the welfare implications of this mismatch are enormous given the scale of fish use. Updating practices to account for fish sentience is one of the largest welfare challenges of our time.