Anaesthesia for fish during handling, sampling and research procedures is an important welfare intervention that reduces stress and pain during unavoidable manipulations.
Fish experience pain and stress during handling, sampling and treatment procedures. The physiological stress response — cortisol release, elevated glucose, immunosuppression — is well documented and impairs welfare and recovery. Anaesthesia significantly reduces acute stress during procedures and improves fish welfare. However, anaesthetic use remains inconsistent in aquaculture outside research contexts, partly due to cost, time constraints and absence of mandatory requirements. The choice of anaesthetic, correct dosing for species and size, water temperature management during anaesthesia and careful recovery monitoring all influence outcomes. Investment in anaesthesia training for aquaculture staff and clear guidelines for routine procedures would substantially improve fish welfare.