In this study, it was aimed to explain the rehabilitation of streams, rivers and fish and the data obtained from the world and our country, as wellas on-site observations and photographs taken as a result of comparative analysis and conclusions and recommendations have been made. DSİ,Ministry of Forestry and Water Works, General Directorate of Nature Conservation and National Parks, Ministry of Environment and Forestryare in charge of stream improvement works in our country. It has seen that the river improvement work started with good intentions but thewrong projects made negatively affect the natural habitats, aquatic plant and animal communities, especially fish. They have lost their originalform and functions to make for humanity fever. It was determined that the projects were planned in such a way that the negative effects of thedelirium were reduced and the nature and wildlife were ignored so as to prevent the loss of soil. Consequently, changes could lead to loss thatwould not be recycled if it does not take due precautions.

The prime objective of the study was to analyze the ecological features and to identify the fish species present along the upstream region of Pechipparai reservoir. Seventeen species of freshwater fishes belonging to 11 genera and 8 families have been recorded. Cyprinidae was the dominant family (6 species) in the study area. Of the 17 species, Dawkinsia arulius belong to the endangered category, Hyporhamphus xanthopterus and Dawkinsia rohani to vulnerable and Ompok bimaculatus to near threatened category. All the 17 fish species are found to be endemic to India and ornamentally appreciated.