Anaesthesia and Analgesia in Fish: Closing the Welfare Gap

Fish were long assumed to be insensible to pain, but scientific consensus has shifted; providing anaesthesia and analgesia for fish procedures is now a welfare priority.

Key Facts

The use of anaesthetics for fish procedures varies enormously across research, aquaculture, and recreational fishing contexts
Tricaine methanesulphonate (MS-222) is the most widely used fish anaesthetic in research and is effective at preventing movement during procedures
Pain-killing drugs such as morphine reduce pain behaviour in fish, suggesting that fish opioid systems function similarly to those in mammals
AVMA guidelines now state that fish are capable of nociception and that pain management should be considered for invasive fish procedures
Commercial aquaculture rarely uses anaesthesia or analgesia during sorting, tagging, or slaughter despite the scale of suffering this involves

Welfare Considerations

The anaesthesia and analgesia gap in fish welfare is one of the largest unaddressed welfare problems in the world given the billions of fish handled in aquaculture annually. Fish in commercial operations are typically sorted, graded, transported, and slaughtered without any pain management. The evidence base for fish sentience and nociception is now strong enough to justify substantial reform. Closing this gap requires both regulatory change and industry investment in humane slaughter and handling infrastructure.

What You Can Do

Advocate for mandatory humane slaughter standards in aquaculture that include effective stunning before killing
Support regulatory frameworks that require anaesthesia for invasive research procedures on fish
Raise awareness among recreational anglers about best practice for handling and releasing fish with minimum injury
Choose seafood certified under standards that include fish welfare handling criteria
Support research into cost-effective, scalable humane stunning systems for commercial fish operations