Effects of 2-phenoxyethanol on anesthetic effect and blood biochemical indexes of juvenile hybrid snakehead (Channa argus ♂ × C. maculate ♀)

To reduce the stress-induced damage risk in juvenile hybrid snakehead (Channa argus ♂ × C. maculate ♀) during aquaculture and research procedures, we examined the anesthetic efficacy of 2-phenoxyethanol at different concentrations (200, 400, 800, 1 200, 1 600, 2 000 mg·L⁻¹) on hybrid snakeheads Body mass: (30±3) g. The effects of the air exposure time after anesthetized fish (0, 3, 6, 9, 12, 15 min), water temperature (20, 22, 24, 26, 28, 30 ℃), and body mass (30, 60, 90 g) on anesthesia were evaluated. Blood biochemical indices were analyzed post-anesthesia. Results show that increasing 2-phenoxyethanol concentrations reduced anesthesia time significantly (p<0.05) and prolonged recovery time (p<0.05), with 800 mg·L⁻¹ as the optimal concentration. Recovery time was negatively correlated with air exposure time, with 100% survival within 0−15 min. Elevated water temperature extended anesthesia time, with no significant differences at ≤2 ℃, but significant effects at ≥4 ℃ (p<0.05). Both anesthesia and recovery times were positively correlated with body mass (p<0.05). 2-phenoxyethanol significantly affected metabolic indexes (GLU, BUN, CRE) and liver enzymes (AST, ALT, LDH) of the hybrid snakeheads, with AST, ALT, and LDH levels remaining elevated post-recovery (p<0.05). In conclusion, 2-phenylethanol is a safe and effective anesthetic for hybrid snakehead, and its anesthetic effect is significantly affected by anesthetic concentration, body mass and water temperature. The ideal anesthetic concentration of 2-phenoxyethanol for 30 g hybrid snakehead is 800 mg·L⁻¹ at 20 ℃, and the safe operation time can reach 15 min.