This study investigated the suitability of wastewater from secondary treatment used in breeding fishes of Carassius gibelio species, and using this fish for human food. For this purpose, metals (Fe, Mn, Cu, Ni, Zn, Cr, Pb, Cd, As and B) in treated effluent and muscle, gill and liver tissues of fish were examined seasonally. It was found that treated effluent was suitable for irrigation and partially available for aquaculture, and the concentrations in fish tissues were over standard values. The values in liver and gill were higher than muscles. The TF (transfer factor) values of all metals examined were observed as >1 in the three tissues and the metals caused bioaccumulation. Concentrations in muscles were found to be 10 to 1000 times higher than in water. Size order of TF and BCF (bio-concentration factor) values in eatable muscle tissue were the same and it was Zn>Fe>Pb>Cu>Ni>Cd>As>Cr>Mn>B. Concentration differences among the tissues for As, Cd, Pb, Ni and B were not significant (P>0.05). Because the correlations between Cd, Mn, Pb and Cu concentrations in tissues and treated effluent were found to be statistically significant, the metals caused bioaccumulation because of treated effluent. HQ (hazard quotient) and BCF values of Pb in muscle had carcinogenic risk levels.