Abstract:The Cyprinus carpio (6 months old) were exposed to water bodies with different concentration of Cr^6+ ranged from 0,0.12, 0.67,1.22, 3.66, 10.97 and 32.91 mg?L^-1, respectively. An increase in growth rote (AGR and ALR) was observed in T0.12 to T3.66 Cr^6+ -treated groups. The results showed that Cr^6+ also affected serum osmolarity and serum electrolytes. The serum osmolality and Na^+ and Ca^2+ concentration were significantly higher in the Cr^6+ - treared groups than in the controls. Increase of serum K^+ was also observed, but it was only significant in T10.97 group. The concentrations of serum Mg^2+ from a few Cr^6+ treated groups were decreased. No obvious serum Cl^- concentration changes were observed. Cr^6+ affected serum hormonal responses. The T3 content in T3.66 group and T4 content in T10.93 group, and the cortisol levels from all the groups treated with Cr^6+ concentration 0.67 and higher were significantly increased. The nutritional contents (crude protein and crude fat) in fish from most of the Cr^6+ treated groups were lower than the control. The concentration of Cr in a fish body treated with Cr^6+ had a distribution pattern: muscle 〈 gill 〈 liver 〈 Intestines. The Cr concentration in fish muscle from group T32 91 (3.00 mg?kg^-1) and the Cr concentration in intestines from group T0.67(2.24 mg?kg^-1 ) and from all the groups treated with higher Cr^6+ exceeded the national maximum limit for food safety.