Analgesia and Pain Management in Laboratory Fish

Growing evidence that fish experience pain and stress has led to greater attention to analgesia protocols in laboratory settings, improving fish welfare in research.

Key Facts

Zebrafish, the most common research fish, have nociceptors and pain-processing neural pathways
Fish show avoidance learning and changes in behaviour consistent with pain experience
Lidocaine and tricaine (MS-222) are commonly used local anaesthetics and euthanasia agents in fish
Non-steroidal anti-inflammatory drugs (NSAIDs) like meloxicam have been studied in fish analgesia
The UK, EU, and many countries now require ethical review and pain minimisation for fish research
Clove oil (eugenol) is used as an anaesthetic in fish; dose and species sensitivity vary widely
Rapid killing methods such as concussion are preferable to prolonged chemical euthanasia

Welfare Considerations

Fish welfare in laboratory settings has historically been undervalued due to uncertainty about their sentience. Scientific consensus now supports that fish experience nociception and likely pain. Inadequate analgesia during surgical procedures, tissue sampling, or euthanasia causes suffering. Best-practice laboratories now use species-appropriate anaesthetics, optimised post-procedural recovery, enriched tank environments, and humane endpoints to minimise suffering. Regulatory frameworks are advancing but implementation varies internationally.

What You Can Do

Advocate for mandatory pain management protocols for all laboratory fish procedures
Support funding for research into fish-specific analgesics and their efficacy
Learn about the Three Rs (Replace, Reduce, Refine) framework for laboratory animal welfare
Encourage transparency from research institutions about their fish welfare standards
Engage with fish sentience science to understand the evidence for fish pain experience