Toxicity and anesthetic efficiency of chloroxylenol on Nile tilapia (Oreochromis niloticus) and goldfish (Carassius auratus)

Abstract

The toxicity of chloroxylenol on Nile tilapia (Oreochromis niloticus) (average total length 3.22±0.49 cm and average weight 0.67±0.01 g) and goldfish (Carassius auratus) (average total length 8.79±0.76 cm and average weight 5.97±1.45 g) were determined by static bioassay method. Fish were starved for 24 hours before and during the experiment. The 5-min median lethal concentration (5-min LC₅₀) of chloroxylenol for Nile tilapia and goldfish were 13.24 and 29.95 mg/l, respectively, with a 95% confidence interval from 11.36-15.67 and 29.05-30.89 mg/l, respectively. The optimal concentration of chloroxylenol as an anesthetic for Nile tilapia and goldfish to produce rapid anesthesia in phase 3 (Stage III: Loss of reflex reactivity) at 2 min and quick recovery were 12.0 และ 24.0 mg/l, respectively, with 100% fish survival after trial 24 hours. The higher concentration of chloroxylenol caused Nile tilapia and goldfish to reach the anesthesia quicker and longer, significantly differed among concentrations (p < 0.05).