Sewage is the water born waste derived from home (domestic waste) and animal or food processing plants. Due to accumulation of sewage and other wastes in these bodies, theirself, regulatory capability is lost. The microorganism decompose the organic matter from the polluted water bodies. Aquatic plants take up water for photosynthesis and therefore deficiency of water takes place there. Fishes eat the small animals and plants only, not the polluted matter.