The mola, Amblypharyngodon mola is commonly known as "mola carplet" is distributed in South Asian countries including India. Mola carplet, Amblypharyngodon mola is a demanding and nutrient rich small indigenous fish available in the Indian sub-continent that has the potential of eradicating malnutrition in developing countries. It is known as a self-recruiting fish species and breeds in water bodies when the ecology and environment suits to it. The knowledge about its exact breeding behaviour and the reproductive characteristics is poor. Though a very valuable species, the population of this fish is getting reduced day by day due to indiscriminate use of pesticides and insecticides and for other anthropogenic reasons also. Hence, to conserve this fish and for the diversification of aquaculture there is a great need to develop the artificial spawning and seed production methods for this species.
Spawning of mola was attempted at ICAR-CIFA under controlled optimized conditions with an objective to get its seed throughout the year. For this about 50-60 numbers of healthy mola brood of 9-months age having mean body weight of 2.04±0.15 g were reared for a period of 2-3 months in cemented tanks. Rearing tank was set up with all optimal conditions that simulate their wild habitat. Removal of 30% water from the rearing tank and flushing of fresh water was done regularly to create a breeding environment. Some bushy plants such as hydrilla were kept in two earthen pots to provide shelter and hiding area for the newly hatched spawn. The water parameters were: total alkalinity 126-130 ppt, pH 7.3-8.0, dissolved oxygen 4-6 ppm, ammonia less than 0.02ppm and the water temperature was maintained at 28-30 °C. Under these conditions mola bred in the cement tanks and as far as possible the adult mola were removed from the tanks to avoid predation of eggs and larvae by them. After 10 days of hatching the larvae/spawn were collected using cotton hapa with utmost care as they die very easily. The young ones were fed with (35% protein) powdered feed and also with plankton on alternate days. By this process 400-500 newly hatched mola seed were produced from each of the 3 rearing tanks (L 8' x W 4" x H 3.8'). The spawn were reared in mini RAS (Re-circulatory Aquaculture System) system having 358 litre water holding capacity with adequate aeration. The young mola attained a mean body weight of 0.032±0.003 g at about 45 days of rearing. Similarly, for spontaneous spawning, the fish were stocked in two earthen ponds (0.04 ha) having nearly 20% area covered with aquatic weed hydrilla. The fish were fed with powdered floating feed twice daily having (35% crude protein). Under these circumstances spontaneous spawning took place twice, once in October and January) at a water temperature of 27 ˚C to 29 ˚C. The hatchlings were reared simultaneously in glass aquaria, cement tanks and earthen ponds environment. The body weight of the A. mola was constantly increased with each passing days post hatching (DPH) and reached 248 mg at 80 DPH from 38 mg at 5 DPH. The present study opens a new dimension in artificial propagation and aquaculture of small indigenous fish species.