Description of the study area: The experiment on life cycle, juvenile carrying capacity and production of freshwater snail (V. bengalensis Lamarck) using different substrates in IMTA pond, was carried out for a period of 3 months from of 4th July to 1st October 2012. Nine experimental IMTA ponds were situated in the south side of wet Laboratory Complex, Faculty of Fisheries, BAU, Mymensingh. Description of the IMTA ponds: The experiment was conducted in 9 (nine) IMTA ponds, each of 1 decimal and having similar shape, depth, basin configuration and bottom type. The ponds were free from aquatic vegetation, completely independent and well exposed to sunlight. The ponds had inlet and outlet systems, but during the experiment the inlet and outlet system was sealed with polythene sheet. Experimental design: Three Treatments were considered named T1, T2 and T3. In each Treatment, three replications were designed. Components of Treatment-1 were 80 carps (Catla, Silver, Rui, and Mrigal) per decimal. Stocking ratio of Catla, Silver, Rui and Mrigal was 3:1:2:2. Three cages were in the Treatment-1 with Shing. Every cage was 1m3 in volume and Shing was stocked as 100/cage. Snail was not stocked in Treatment -1. Components of Treatment-2 were 80 carps (Catla, Silver, Rui, and Mrigal) per decimal. Stocking ratio of Catla, Silver, Rui, and Mrigal was 3:1:2:2. Three cages were in the Treatment-2 with Shing. Every cage was 1m3 in volume and Shing was stocked as 100/cage. Stocking of snail was 250 g per decimal in Treatment-2. In the Treatment-3 were 80 carps (Catla, Silver, Rui, and Mrigal) per decimal were stocked. Stocking ratio of Catla, Silver, Rui, and Mrigal was 3:1:2:2. Three cages were also in the Treatment-3 with Shing. Every cage was of 1m3 in volume and Shing was stocked as 100/cage. Stocking of snail was 250 g per decimal in Treatment-3. Four trays water spinach (kolmi in Bangali) were in Treatment -3. Compost preparation: Compost was made on the IMTA pond dike by digging a pit on the dike and keeps a polythene sheet (9 feet) in this place as the raw materials were not directly contact with the soil. Before stocking of carps, Shing and snails in the pond, pre-stocking compost was made mixing mustard oil cake (1 kg per decimal), urea (0.25 kg per decimal), cow dung (1 kg per decimal) and water hyacinth (0.5 kg per decimal). After stocking carps, Shing, and snail, compost were applied at 15 days interval. Post stocking compost was made by mustard oil cake (1 kg per decimal), urea (0.1 kg per decimal), cow dung (1 kg per decimal) and water hyacinth (0.3 kg per decimal). IMTA pond preparation: During pond preparation dikes were repaired, weeds and undesirable fish species and other aquatic animals were removed by pond drying and repeated netting. Before starting culture, IMTA ponds were treated with lime at the rate of 1 kg per decimal. Hapa set up for life cycle observation of snail (V. bengalensis): For life cycle observation of freshwater snail two hapa were set up in Treatment-2 and Treatment-3. Every hapa was rectangular shaped and sized was 60.96 cm × 15.24 cm × 45.72 cm. For the protection from direct sun light banana leafs, bamboo sticks, plastic pipe, were placed in hapa. Stocking of snail: After setting the hapa 100 adult snails were stocked in each. The range of average lengths of adult snails were 2.4 to 2.6 cm and average weight were 2.6 to 2.9 g. Feeding: The experimental IMTA ponds were monitored daily to observe any abrupt changes in the environment and the condition of snail. As the IMTA ponds were also used as carps and Shing culture, therefore supplementary feed was given twice a day. At 15 days interval, compost was provided to the pond for satisfactory growth and breeding of snails. Collection system of snail for sampling: For observation of life cycle, juveniles carrying capacity and production snails were collected at 7 days of interval. Collections of snail from bamboo pole, banana leafs and plastic pipes were done carefully so that any snail was not dropped into the pond. Ekman Dredge (6”× 6”) was used to collect snail from bottom. Twenty adult snails were sampled from each hapa for observation of egg, embryo and juvenile in the laboratory. Investigations in the laboratory: Male-Female Identification Adult snails were taken in the laboratory after collected from hapa. At first, snails were washed by running tape water. Male-female were identified by the measurement of operculum, tentacle, body shaped, length and weight. For the measurement, electronic balance, measurement scale, forceps, niddle and Magnus biological microscope (model: MLX-B) were used. This microscope has the special capacity to deliver the photos of small objects in the computer systems. Eggs, embryo, juvenile observation An adult snail was going through 3 stages in their body, such as eggs, embryo and juvenile. Eggs, embryo and juvenile were identified by using magnifying glass and Magnus biological microscope (model: MLX-B). Observation on young snail: After 1 week young snail craw out of the mother cavity and young snails were found in the hapa during sampling .Young snails were collected from plastic pipe, bamboo pole which were palced in the hapa. Measuring scale and electronic balance were used for the measurement of length and weight of snails. Observation on adult snail: Adult snails were collected from plastic pipe, bamboo pole and net. Measuring scale and electronic balance were used for the measurement of length and weight. Snail production assessment: For measuring production of snail per 1 decimal area of each IMTA pond was harvested with Ekman Dredge and how many snails were found were assessed to show the production of snail in different Treatments. Studies on water quality parameters: Throughout the experimental period, water quality parameters were recorded weekly. Water temperature (ºC), pH and dissolved oxygen (mg/l) were measured every week at the suitable place near the pond site at 9.00 AM to 10.00 AM. Data analysis: The data of male and female snail and juvenile carrying capacity of female were analyzed using analysis of variance (ANOVA) to assess the significant differences (Appendix i, ii and iii). The statistical software SPSS was used for analysis. The descriptive data was presented by tabular forms and graphically.