The scientific evidence for fish pain and sentience has grown substantially over two decades, reshaping regulatory frameworks and raising urgent questions about the welfare of the billions of fish caught and farmed annually.
Fish sentience evidence has shifted from contested to compelling over the past two decades. Multiple species demonstrate nociception, avoidance learning, stress responses, and behavioural changes consistent with pain that are reversed by analgesics - the gold standard for pain evidence. Despite this, fish welfare remains poorly protected in practice. Wild-caught fish die by suffocation, crushing, or live processing without stunning. Farmed fish may receive improved welfare standards under schemes like RSPCA Assured, but most farmed fish globally are killed without humane slaughter. The scale of fish exploitation means that improving fish welfare has enormous potential impact on the total amount of animal suffering in the world.