Water of Tulashi tank is utilized for pisciculture, irrigation and domestic purposes. It is an urgent need to assess the water quality. The Physico-chemical parameters of Tulashi tank were studied during January to December, 2011. The results discovered that there was a significant seasonal variation in some physico-chemical parameters. Water temperature ranges from 22.16 to 28.64°C, turbidity 0.68 to 2.95 NTU. Transparency 32.45 to 44.56 cm. The pH 7.10 to 8.85, DO 6.48 to 8.52 mg/l, CO2 1.89 to 5.98 mg/l, Alkalinity 126.42 to 162.42 mg/l, Total Hardness 82.46 to 156.26 mg/l. Phosphate 0.19 to 1.94 mg/l, Nitrates 2.17 to 12.45 mg/l and Chlorides 37.26 to 43.48 mg/l. Above values are within the acceptable limits of BIS standard for drinking water therefore the water is potable and suitable for pisciculture.