Anesthetic agents for fish reduce stress and pain during procedures including vaccination, sampling, and transport, with significant welfare benefits when properly applied.
Fish anesthesia is an underutilized welfare tool that significantly reduces the suffering associated with routine aquaculture procedures. Without anesthesia, fish handling involves acute stress responses including cortisol elevation, immune suppression, and escape behavior that can cause physical injury. Anesthesia eliminates the awareness component of procedural stress while allowing necessary work to be performed efficiently. The welfare case is strongest for procedures involving out-of-water time — tagging, sampling, and vaccination — where conscious fish experience both the procedure and the stress of air exposure simultaneously. Practical barriers to wider anesthetic use include cost, regulatory requirements, and lack of training; investment in stockperson education and simplified protocols would increase adoption rates with significant welfare benefit.