The Municipal Sewage water are discharged into low level areas, in streams and lands which finally accumulate in the form of large ponds and affects the environment. The sewage sample was collected from Singanallur station of sanganur canal of Coimbatore.1/10th of 72 hour LC50 value was taken as sublethal concentration for sewage water. After the experimental exposure (72hours, 10days, 20days) fishes were sacrificed and organs like gill, liver, kidney used for histopathological studies. It showed degenerative changes in gills, symptoms of general necrosis, cloudy swelling in liver and dilated glomeruli, cellular hypertrophy in kidney.