Abstract: The nutritional requirements of protein,fat,carbohydrate,cellulose and mineral mix of Leiocassis Longirostris (average weight:60±4.9 g/fish) were studied.The L18 (6×36) table of orthogonal design method was employed to formulate eighteen diet combinations.Feeding experiments were conducted in 400×100×120 cm pool of 4000 L in capacity.The water flow maintained at 100 L/h.,had a temperature of 25.3±1.3℃,a dissolved oxygen of 4.9±1.1 mgO2/L and a Ph7.0-7.4.The daua of the experiments ware analysed with the method of analyses of variance and the multiple method or Tukeys Q procedure.The results of feeding experiment show that the effects of nutients on the specific growth rate (SGR),protein efficiency ratio (PER) and food conversion ratio (FCR) ranked in the following order:Protein>fat>carbohydrate>cellulose.Thus,protein was found to be the main nutrient in the present experiment.The daily nutritional requirements for the SGR.PER and FCR of Leiocassis longirostris were found to be 1.2-1.3 g protein,0.18-0.27 g fat.0.75 g carbohydrate and 0.24 g cellulose with an ingredient of 0.1 g mineral mix in the diet per 100 g fish (wet body weight) per day.Tramsferring to percentage composition,the diet should contain 40%-43.3% protein,6%-9% fat,25% carbohydrate and 8% cellulose with additional 4% mineral mix.The diet formulated according to this composition and fed to the fish at the rate of 3% body weight daily supported the maximum growth rate.There was a direct correlation between body fat (y) and the nutritional protein level the diet (x),the formula being y=6.6648+5.6229 x (r=0.9198).When there was a negative correlation between body fat (y) and the ash (x),the formula being y=10.2343-2.4314 x (r=0.9320).