Among the wide majority of pesticides, dichlorvos (2, 2-dichlorovinyl dimethyl phosphate), a organophosphate compound, is commonly used as agricultural insecticide. It is extremely toxic to non target organisms like fish and hampers fish health through impairment of metabolism, sometimes leading to death. As one of the few organophosphates still registered for use, dichlorvos has elicited worldwide concern for many reasons. This study is a review of potential adverse effects of dichlorvos in fish.