Efficacy of clove oil and rosewood oil as anesthetics on gold fish (Carassius auratus)

Anesthetics have an essential role in aquaculture operations because they minimize physical injury during various handling practices such as sampling, weighing, length measurement and tagging, which decreases stress on fish. Many fish farmers are involved in using alternative fish anesthetic agents with minimal side effects to life such as herbal essential oils. This study aims at investigating the efficacy of clove oil and rosewood oil as anesthetics on goldfish Carassius auratus.Anesthesia effect of both oils was tested in six different concentrations (i.e., 100, 150, 200, 250, 300 and 350 mg/l of water) on ten fish between 6–25 g weight and 9–14 cm length. The efficacy of both oils was assessed on the basis of the fish behavior. The induction time (min) was assessed by loss of swimming (LS), partial loss of equilibrium (PLE), final loss of equilibrium (FLE), and medullar collapse (Mc). The fish were observed for balance and response to a tactile stimulus in each treatment. Both clove oil and rosewood oil contributed well as anesthetics as they caused loss of equilibrium and swimming ability in the goldfish. In contrast, clove oil generated more rapid induction, prolonged recovery, and a narrow margin of safety. Fish farmers should use natural and environment friendly anesthetic agents instead of chemical ones, as they may alter negatively the growth and health of fish.