Fresh water prawns are caught from the rivers, lakes and other fresh water areas through out the state. Some species are also caught from the brackish water takes during months when the salinity is low and prawn migrates temporarily, chiefly for breeding.
For profitable fish culture, it is necessary to select, such species of fish, which can utilize the natural and artificial food to the maximum, extend and grow rapidly to a large size. Species that fulfill the following conditions can considered suitable for culture.
Classification of water pollution depends on the criterion used for categorization of pollution. Based on the medium in which pollutants occur, types of water pollution may be distinguished as fresh water pollution and marine pollution.