Fish Pain and Anaesthesia in Veterinary Practice

Growing scientific consensus that fish experience pain has led to increasing use of anaesthesia in veterinary and research procedures, improving welfare for these widely overlooked animals.

Key Facts

Fish possess nociceptors, opioid receptors, and neurochemical systems associated with pain processing in mammals.
The 2003 Sneddon et al. study in trout provided foundational evidence of fish pain responses.
Tricaine methanesulphonate (MS-222) and clove oil are the most commonly used fish anaesthetics.
Many routine veterinary procedures in fish including surgery, sampling, and tagging now use anaesthesia.
Pain relief post-procedure reduces recovery stress and improves healing outcomes in fish.

Welfare Considerations

The application of anaesthesia and analgesia to fish represents a significant advance in aquatic animal welfare. Fish undergoing surgical procedures without anaesthesia show extreme stress responses, impaired immune function, and higher mortality. Veterinary and research settings are increasingly mandating fish anaesthesia for all invasive procedures. The challenge for production aquaculture is scaling welfare-conscious practices including humane slaughter to billion-fish operations, where the welfare stakes are highest.

What You Can Do

Support aquaculture certification schemes that require humane slaughter standards for farmed fish.
Choose seafood from producers who publish their slaughter and handling welfare protocols.
Advocate for mandatory fish anaesthesia standards in research and veterinary settings.
Support science communication organisations working to raise public awareness of fish sentience.
Reduce farmed fish consumption or choose plant-based alternatives to minimise demand.