Semi-static bioassay experiment was conducted to ascertain Butrylacetycholinesterase enzyme activity in liver and plasma, liver glycogen and plasma glucose content, haematology as well as behaviour of Clarias gariepinus (mean weight 24.52±1.64 g) to varying concentrations (0, 0.4, 0.8, 1.6 mg L -1 ) of Dichlorvos for 96 hours. Butrylacetycholinesterase activity in liver was significantly (P <0.05) inhibited all through the exposure duration to 0.4, 0.8 and 1.6 mg L -1 of DDVP compared with control group of fish. Similarly, plasma BuChE activity was inhibited all through the exposure duration to 1.6 mg L -1 DDVP compared to control. There was a significant (P <0.05) inhibition in HB, RBC and MCV of exposed fish after 24,48, 72 and 96h to 1.6 mg L -1 DDVP compared to the control but PCV and WBC were significantly elevated after 72 and 96h to 1.6 mg L -1 DDVP compared to the control.Plasma cortisol and liver glycogen were significantly inhibited after 72 and 96 h to 0.8 and 1.6 mg L