The in vitro digestibility and growth performances of Sea bass (Lates calcarifer (Bloch)) and channel catfish (Ictalurus punctatus) fed with feed mixed with pineapple peel (PA) and papaya peel (PP) in a Recirculating Aquaculture System (RAS) were carried out. The control feeds were 40 % protein for cultured sea bass and 25 % protein for cultured channel catfish. Four treatments with 3 replications of fish fed with control, pineapple juice 5 ml/kg feed (PA), papaya peel 5 g/kg feed (PP), a combination of 5 ml/kg feed pineapple juice and 5 g/kg feed papaya peel (PP+PA). The experiment was conducted for 90 days. The results showed that in vitro digestibility of carbohydrate and protein with enzymes from sea bass was highest in PA and crude enzymes from channel catfish was highest in PP (p>0.05). Growth performances of sea bass showed that weight gain, length gain, average daily gain and survival rate were highest in PA+PP; however, all treatments was not significantly different (p>0.05). Growth performances of channel catfish showed that weight gain, length gain and average daily gain highest in fish fed with PP feed (P<0.05) from a control. The cost of PA+PP for sea bass was 81.21 baht per kilogram while the cost of PP for channel catfish was 43.44 baht per kilogram. The water quality in this research was within the recommended levels by the Pollution Control Department.