The use of anaesthesia in fish during scientific research is a rapidly evolving area as evidence of fish sentience strengthens the ethical case for pain and stress mitigation in aquatic research.
For decades fish were excluded from welfare protections in research settings based on assumptions about their limited sentience. Accumulating evidence including studies on pain avoidance learning, analgesic seeking and cortisol stress responses now challenges this exclusion. Anaesthesia during surgical procedures, tagging and sampling reduces acute stress and potential pain experience. As research norms evolve, the expectation that fish used in experiments receive appropriate anaesthetic and analgesic protocols is increasingly embedded in ethical review processes and regulatory frameworks.