The experiment was conducted in 12 earthen rain-fed mini ponds of each 30m2 size situated behind the Fisheries Faculty Building, Bangladesh Agricultural University (BAD) Campus, Mymensing during the month from July to October’98. The water depth was maintained to maximum of 1.2 m using fine meshed PVC overflow pipe (2 inches diameter) on the bank fixed at 1.2 m above the pond bottom. All the ponds were of similar size, depth, basin configuration and the bottom type including water supply facilities from a deep tubewell. Undesirable species in the ponds were eradicated by repeated netting followed by application of rotenone (20 g/40m2 ). Liming was performed at the rate of 1 kg/40m2
• For formulation of experimental diets, different feed ingredients such as fish meal, shrimp meal, soybean meal, mustard oil cake, sesame meal, wheat bran, rice bran, oyster shell and vitamin premixes were collected from Dhaka and Mymensingh local markets.
Five experimental diets were formulated to contain 32% protein. Diets were also formulated to be isoenergic as far as possible to maintain similar energy levels.
A SABINCO shrimp diet (starter-III) from Saudi-Bangla Fish Feed Ltd, Bhaluka, Mymensingh was used as the control. All the collected ingredients were ground finely and sieved through 0.5 mm mesh. After sieving all the required amount of dry ingredients along with vitamin premix were weighed according to the formulae of experimental diets. The well mixed ingredients were then put into the pellet mill for the preparation of pelleted feed of size 3 mm.