Most farmed fish worldwide are slaughtered without any form of stunning, meaning they experience the full pain and distress of the killing process. This is a major and addressable welfare failure.
The evidence that fish feel pain is now scientifically robust. Fish have nociceptors, endogenous opioid systems, and show behavioural and physiological responses to noxious stimuli that parallel those in mammals. Despite this, the farmed fish industry has been extraordinarily slow to adopt stunning at slaughter — a change that costs relatively little but would eliminate prolonged suffering for billions of individuals each year. The technical solutions exist: percussive, electrical, and CO2 stunning methods are all commercially available and used by welfare-conscious producers. The barrier is largely economic and regulatory: slaughter welfare standards for fish lag decades behind those for mammals and birds in most jurisdictions.