Indonesian shortfin eel, Anguilla bicolor bicolor is one of the eel species that high market demand both for local and export. Feeding frequency is an important that related to production for culture. The purpose of this experiment is to determine the optimal feeding frequencies on survival and growth of shortfin eel at glass eel to elver stages cultured in a recirculating aquaculture system. Four treatments of different feeding frequencies and three replicates each were performed. The treatments were as followed A) 1 time a day; B) 2 times a day; C) 3 times a day; and D) 4 times a day. The result showed that the feeding frequency affect the survival, length and weight growths, and glucose value. The best of survival rate (82.61±3.15%), weight (1.91±0.28 g) and length (10.64±0.45cm) found at feeding frequency 3 times a day compared to the others (P<.0.05). Blood glucose value increases with increasing feeding frequency. Water quality such as dissolved oxygen (DO), temperature and pH were within the optimal range. Three times a day of feeding frequency is recommended for applying on glass eel culture in a recirculating aquaculture system.

Water quality is the main factor that should have been considered in the part of aquaculture where the fish will grow in the optimal environment circumstances that suit biological demands. Adding the aeration aims to increase dissolved oxygen and turbulence. The objectives of this study is to see how different aeration rates affect the survival and growth of Mahseer Tor soro. The research used 12 aquariums, each sizing of 66x24x30 cm. Fish’s stocking density was three individuals per Liter for each aquarium. The randomization design was completed with four treatments and three replicates. The different aeration rate as a treatment were A) 0; B) 1000; C) 2000; and D) 3000 ml/minute. The results show that the highest absolute length (1.73±0.611 cm) and survival rate (98.33%) at 1000 ml/minute were the highest where the blood profile such as blood glucose, the hematocrit, haemoglobin, and erythrocyte values at 1000 ml/minute was the lowest compared to other treatments (P<0.05). The best of aeration rate for seed culture of masher, Tor soro is 1000 ml/minute, which has resulted in dissolved oxygen is ranging from 7.05–7.71 mg/L.