In the present study investigation of histological alterations produced by alkaline conditions of polluted water of ponds on liver, kidney, muscle and gill of C. catla a teleost, surface feeder, omnivore fish, has been made. Study indicates towards hazardous effects of water pollution on fishes at molecular level. The histopathological changes found in liver of Catla catla collected from polluted ponds, shows degeneration of hepatic cells, necrosis in cytoplasm, necrotic cells, pyknotic nuclei and formation of vacuoles. In kidneys alterations include degeneration and atrophy of renal tubules, highly enlarged glomerulus, pyknotic nuclei, tubular necrosis, enlarged lumen of tubules hypertrophied corpuscles of stannous. In muscles alterations found are vacuolar degeneration in muscle bundles, edema between muscle bundles, splitting muscle fibers, development of necrotic areas, degenerating muscle bundles. Histopathological changes in their gills include destruction of primary gill lamellae and secondary gill lamellae, proliferation of inter lamellar cells, formation of vacuoles and hyperplasia of gill lamellae due alkaline water