The aim of this work was to find the seasonal variations of physico-chemical properties of the Dejla Dewda reservoir. The physico-chemical characteristics have been studied and analysed in the present investigation during Nov 2016 to Dec 2017.Water samples were collected from three sampling stations, changes in the physico-chemical parameters of water, such as Water temperature, transparency, alkalinity, chloride, sulphate, nitrate, phosphate, Total dissolved solids (TDS), Biological oxygen demand (BOD), Dissolved oxygen (DO), Chemical oxygen demand (COD) and pH were analysed. The result was compared with the water quality standard of WHO. Between various physico-chemical parameters systematic calculation of average and standard deviation was done to compare the water quality level at different stations. During the investigation period of one year, 24 species of fishes belonging to 03 orders and 06 families were recorded. Therefore, monitoring of the water quality of sampling sites of Dejla Dewda reservoir should be done at regular intervals to facilitate the growth of fish species. It was observed during the study that this reservoir water is not much polluted and supports high diversity of aquatic animals.