Anesthesia in fish is used for routine aquaculture procedures and research interventions, with welfare implications depending on the agent used and the skill of application.
Fish anesthesia occupies an interesting welfare position: it is often used to enable welfare-positive procedures (health assessments, surgical interventions, sampling) while itself carrying welfare costs if improperly applied. Overdose, prolonged exposure, and poor recovery conditions all cause welfare harm. The choice of anesthetic agent matters — some produce smoother induction and recovery than others, and this welfare dimension should drive agent selection alongside efficacy and regulatory approval. Supporting research into better fish anesthetic agents and protocols advances welfare in a relatively neglected area of applied fish welfare science.