The study was conducted from August to November 2011 in two earthen ponds of Syedgram, Muktagachha Upazila of Mymensingh district for the experimental purpose. The ponds were equal in depth, basin, configuration and pattern including water supply facilities. The water depth was maintained at a maximum of 4 feet. These were well organized inlet and outlet system to maintain suitable water level. The ponds were surrounded by fine meshed nylon nets to prevent the escaping of fishes. Water quality was maintained properly through routine exchange of water. The size of two ponds were 20 and 60 dec. with Thai koi monoculture and thai koi polyculture along with rui, catla, mrigal, shing, tilapia in T1 and T2. Two different stocking densities such as 2000 koi fry/dec. in the T1, 1000 koi fry/dec and rui, catla, mrigal, tilapia fishes in the T2 respectively. After pond drying, lime and green geolite was applied @ of 150 and 80 kg/ha respectively. Fertilization was carried out after 4 days of liming into the pond with urea and triple super phosphate together @ of 250 gm/dec. TSP and Urea were applied after mixing together and dissolving in a plastic bucket before 24 hours of application. After 3-4 days having a plankton bloom, water level was gradually increased up to 4 ft. Six barriers made of bamboo were placed in the middle of the pond. Barrier structure made of bamboo and covered with the small mesh size nets. The total length or height of each barrier was 7 feet. These barriers were inserted into the pond bottom vertically. The newly hatched fry were fed with formulated nursery feed (egg and yolk, maize powder, polish powder etc.). When the fry became about 1 cm, 1.25 cm length and weight were about 0.11g, 0.15g, then they were stocked in the research monoculture and polyculture ponds. Commercial pellet feeds named “Agro Bangla and Paragon fish feed” was selected for the experiment. The proximate composition of different types of “Agro Bangla and Paragon fish feed”. At the beginning of the experiment feed was supplied at the rate of 40% of the body weight of reared Thai koi and gradually it was readjusted from 20%, 12%, 10%, 8%, 5% and 4%, sampling was done regularly. Thai koi were feed three times daily at every 8 hours intervals and each time. Water quality parameters such as pH, dissolved oxygen (DO) and temperature were recorded after 15 days interval. Harvesting was done at the evening of 20 November. During each sampling 20 fish were collected from each pond. Weight gain, average daily gain (g), percentage weight gain, survival rate (%) and specific growth rate (SGR), collected for determine the net production. All data were processed and analyzed statistically by using Microsoft Excel program and SPSS (Version 12.0).