Assessment of acute toxicity levels and dipping bath test for some commonly-used drugs on Pangasias sutchi

The present experiment was conducted to study the effects of different drug formulations on controlling the diseases of Pangasias sutchi in fresh water.The four drug formulations,viz.,CaO;CuSO4∶FeSO4(5∶2);trichloroisocyanuric acid(TCCA) and dipterex,were given to Pangasias sutchi juveniles(4.5-7.3 cm in body length),and acute toxicity was determined at 24.9-27.8℃ of water temperature,7.5-8.3 of pH and 4.0-5.8 mg/L of dissolved oxygen.The dipping bath of NaCl,KMnO4 and polyvenyl pyrrolidone(PVP) on Pangasias sutchi was carried out.The descending order of median lethal concentrations of drugs,affecting the juveniles,after 96 hours was as follows: CuSO4∶FeSO4(5∶2)DipterexTCCACaO,with safe concentrations of 0.057,0.400,0.130,60.290 mg/L,respectively.In dipping bath experiment,the suitable NaCl concentration was found to be ranged from 2-2.5%,and the PVP and KMnO4 may be used in normal dosage(1.0-1.5,15-20 mg/L) in the dipping bath.