Fish anaesthesia using agents including MS-222 and clove oil is necessary for research and husbandry procedures; welfare-conscious protocols minimise stress and recovery time.
Fish anaesthesia welfare requires attention to induction, maintenance, and recovery. The induction process should be smooth and rapid to minimise time in an aversive transitional state. Maintenance at the correct dose prevents excess stress and allows procedures to be completed efficiently. Recovery monitoring ensures fish have fully regained normal swimming and orientation before being returned to normal housing. The stress of anaesthesia induction itself is significant, creating welfare trade-offs between the harm of anaesthesia and the harm of the procedure being avoided through its use. Research into less stressful induction methods and lower-impact agents is ongoing.