Studies on the toxicological effects of some chemicals on the health condition of some farmed fish

In this study a total number of 660 fishes (330 were Oreochromis niloticus and 330 were Clarias gariepinus) were obtained from Abbasa fish hatchery were used to investigate the toxicological effect of heavy metal and herbicide.1. Toxicity of Zinc sulphate on Oreochromis niloticus:The 96hrs LC 50 of Zinc sulphate in Oreochromis niloticus fingerlings was 545.6 mg/L. The fish at acute toxicity showed hyper excitability and fighting against each other and skin surface carry excessive amounts of mucus, while at chronic toxicity showed Concerning to hematological parameters there were found decrease in Hb, RBCs and PCV % while increase in ALT,AST, Urea, Creatinine and Cortisol.Oreochromis niloticus exposed to 1/3 96hrs LC 50 of zinc sulphate showed difference in behavior, histopathological and hematological parameters in fish during exposure and after recovery .The residues of zinc in muscle and gills of Oreochromis niloticus were time and concentrations dependant.