In this study, the effects of concentration and exposure time of Cu and Pb on plasma levels of Na⁺, K⁺, Ca⁺⁺, Mg⁺ and C^-l of Cyprinus carpio and Oreochromis niloticus were tested at varying concentrations of metal in the medium and over different periods of time. Fish were exposed to 0.1, 0.5 and 1.0 mg/L Cu and Pb over periods of 10 and 20 days and ion distributions of copper and lead were determined using spectrophotometric method. Plasma ion (Na⁺, K⁺, Ca⁺⁺, Mg and Cl^-) levels effected by Pb and Cu. In both species, blood serum Na+ levels decreased after periods tested at exposure to copper while increasing at exposure lead. O. niloticus blood serum K⁺ levels increased with effect of Cu and Pb concentrations. In C. carpio Cu concentrations blood serum K⁺ levels increased while decreased with effect of Pb concentrations after 10 and 20 days of exposure. Ionize Ca⁺⁺ levels of blood serum in O. niloticus decreased at high concentrations of Cu and in all the concentrations of Pb. In C. carpio blood serums ıonize Ca⁺⁺ levels decreased at exposure to copper while increasing at exposure to lead after periods tested. In all the concentration of Cu and Pb and periods tested, blood serum Mg⁺ levels decreased in O. niloticus but an increase was observed in C. carpio. In both species, blood serum Cl^- levels while increasing at copper exposure; it was seen that decreasing at lead exposure.