acute toxicity and the effects of copper sulphate (cuso4.5h2o) on the behavior of the black fish (capoeta fusca)

background: the development of toxicity tests regarding toxic responses of different fish species could be more effectively used in predictive toxicology and risk assessment. in this study lethal concentrations (lc50-96 h) values of copper sulphate an important toxic industrial pollutant, on capoeta fusca were determined. behavioral changes at different concentrations of cuso4 were determined for the c.fusca. methods: the sample fishes were collected from qanat in birjand and were transported to the laboratory in polythene bags. the exposure time of fish to cuso4 was 96 hours. mortalities were recorded at 24, 48, 72, and 96 hours of exposure, and the dead fish were removed regularly from the test aquariums. physicochemical parameters, such as dissolved oxygen, ph and total hardness of aquaria were monitored daily. results: the lc50 values for cuso4 at 24, 48, 72, and 96 h of exposure, were 43.62, 12.6, 7.66, and 6.85 mg/l, respectively. the median lc50 value of cuso4 for c.fusca was found to be 6.928 mg/l by epa method and estimated to be 6.787 mg/l with spss statistical software. conclusion: the mortality decreased with time, and most of the deaths occurred during the first 24 h. in addition, behavioral changes increased with increased concentration. this metal is an important constituent in industrial effluents discharged into freshwaters. the results obtained in this study clearly revealed the fact that it is necessary to control the use of a heavy metal such as copper.