Effect of 2-phenoxyethanol as an anesthetic on the stress parameters of goldfish (Carassius auratus)

Due to the avoidable side effects of anesthetics in aquaculture, the study of stress factors in fish is one of the best ways to identify their side effects. The aim of this study was to evaluate the effect of different concentrations of 2-phenoxyethanol (2-PE) as an anesthetic on the stress indicators levels (glucose and cortisol). Time to induction and recovery from anesthesia of this fish was investigated at effective concentrations of 0.1, 0.3, 0.5 and 0.7 ml/L 2-PE. The results showed that exposure to low concentrations of this anesthetic (0.1 and 0.3) causes deep anesthesia to occur for a longer period of time and its recovery time is shorter and vice versa. Plasma cortisol levels significantly increased at concentrations of 0.1 and 0.3 ml/L 2-PE compared to the control group and at higher concentrations (0.5 and 0.7) cortisol levels significantly decreased (P <0.05). According to the results, the use of lower concentrations of 2-phenoxyethanol (0.1 and 0.3 ml/L) causes stress in fish, so higher concentrations (0.5 and 0.7ml/L) of 2-PE are recommended for anesthesia of goldfish.