.Materials and Methods
Study Area and Experimental Design
Experiments were carried out at the rearing ponds of three fish farms of Shibpur, Gouripur, Upazila and Choronikhola Ishorgong Upazila, Mymensingh district of Bangladesh for a period of 100 days from April to July, 2012. The selected nine earthen rearing ponds had around 0.35 ha surface area and an average depth of 1.0 m. The ponds were with almost similar specification in size, depth, basin conformation, contour and bottom type. Three treatments of different stocking density of koi fry were applied with three replicates each. Foizoddin fish Farm, Alamin fish farm Shibpur, Gouripur and Abid fish farm Ishorgong Upazila, Mymensingh was designed for treatment T1, T2 and T3. Pond Preparation and Fertilization