Anaesthesia reduces the stress and pain of handling procedures in farmed and research fish — and its appropriate use is an important welfare tool that is underutilised in many aquaculture operations.
Fish anaesthesia significantly reduces the welfare cost of necessary handling procedures — vaccination, sorting, sampling, and treatment. Without anaesthesia, fish handling causes acute stress responses including cortisol spikes, immune suppression, and physical injury from struggling. With appropriate anaesthesia, fish can be handled with minimal physiological disruption. The barrier to routine use is primarily economic and logistical — anaesthesia adds time and cost to operations. Building anaesthesia into standard protocols for common handling events would be one of the most impactful welfare improvements in aquaculture.