The experiments were conducted to study of the acute toxicity of Cyprinus carpio and Rutilus rutilus by added copper salt in basins. 13 fishes with average weight of 2±0.5g to Rutilus rutilus and 20±2.2g Cyprinus carpio were exposed to different concentrations of copper salt respectively. The experiments were done by Static Method during 96 hours. A group of fish was considered as control samples. The different concentrations of copper such as 0, 0.1, and 0.2, 0.3, 0.4, 0.45 and 5mgL-1 were used to Rutilus rutilus and Cyprinus carpio fishes. Under stable condition (TOC and pH), the lethal concentration of copper was measured of 0.4mgL-1 and 0.45mgL-1 to Rutilus rutilus and Cyprinus carpio respectively during of 96 hours. The results indicated the significant differences were observed between treatments of fish with each other and also with the control samples. With increasing of copper in each treatment, the mortality rate of fish significantly was increased. Histopathological findings showed that major lesions were hemorrhage, hyperemia, hyperplasia and epithelial cells necrosis in total fish. Also in the lesion fish were observed degenerated tubules of their kidney, expansion of Bowman's capsule and hepatocytes necrosis.