The present study investigated the potential changes in hematologic parameters and histology of fish Heteropneustes fossilis when exposed to industrial waste water of different concentrations. The toxicant enter into the fish body from different rout, inhalation, dermal oral, and other several rout for entering in the fish body. The blood parameters of fish H. fossilis control group and treatment were investigated on 1st, 5th, 10th, and 20th days of experiment, hematologic variation was observed in RBC, WBC, MCV, MCH, and MCHC count. Histopathologic changes in liver, intestine, gill, muscle, and heart showed increasing degrees of damage in the tissues in correlation with the accumulation pattern of pesticides, while liver, intestine, gill, muscle, and heart of control group exhibited a normal architecture. Toxic effects of pesticides vary in different organs of the fish H. fossilis significant. The fish exposed to higher concentration showed uncoordinated alterations in behavioral responses, especially erratic and jerky swimming, physiologic, malformation, histologic, hematologic and biochemical changes, frequent surfacing and in gulping, mucus secretion, an increase in opercular movement, and copious secretion of mucus of all over the body.