Abstract: To explore the toxicity of three common aquatic drugs to the first generation of artificial breeding of juvenile Mystus macropterus, and to evaluate the safety of drug use, under the hydrostatic conditions of water temperature 26-28 ℃, pH 7.2-8.3 and dissolved oxygen 6.5-8.3 mg/L, the acute toxicity test was carried out on juvenile M. macropterus with body length (9.47±0.39) cm and body weight (7.56±0.77) g by using povidone iodine, chlorine dioxide and glutaraldehyde and benzalkonium bromide mixture. The results showed that the median lethal doses of povidone iodine at 24, 48 and 96 h were 18.410,17.610 and 17.210 mg/L, respectively. The safe concentration was 4.720 mg/L. The semi-lethal doses of chlorine dioxide at 24,48 and 96 h were 6.000, 5.790 and 5.420 mg/L, respectively. The safe concentration was 1.620 mg/L. The semi-lethal doses of glutaraldehyde and benzalkonium bromide mixture at 24,48 and 96 h were 1.030, 0.890 and 0.830 mg/L, respectively, and the safe concentration was 0.20 mg/L. The sensitivity of the first generation of juvenile M. macropterus to the three drugs was as follows: glutaraldehyde and benzalkonium bromide mixture > chlorine dioxide > povidone iodine. Chlorine dioxide and povidone iodine could ensure aquaculture safety for the first generation of juvenile M. macropterus under standardized application conditions.

Key words: Mystus macropterus, aquatic drug, acute toxicity, semi-lethal concentration, safe concentration