Aquaponic refers to any system that combines conventional aquaculture with hydroponics in a symbiotic environment. In this study, catfish was cultured with green cabbage. The aim of this study was to observe catfish growth in aquaponics system. The growth parameters measured included feed consumption (g/day/fish), growth (g), growth rate (%/day), mean metabolic body weight (kg 0.8), metabolic feed intake (g/ kg 0.8 /day), relative growth rate per metabolic weight (g/kg 0.8 /day), relative feeding rate (%BW/day), relative feeding rate per metabolic weight (g/kg 0.8) and feed conversion. Factorial randomized trial was used with two factors namely fish stocking density (P) and plant substrate composition (S) with three replications. Stocking density factor consisted of two treatments which were 75-125 individuals per m 2 (P1) and 126-175 individuals per m 2 (P2). The composition of the substrate included two treatments, namely S1 (70% gravel+30% palm fibres) and S2 (70% pumice+30% palm fibres). The data shown that there is no significant difference of substrate and interaction (stocking density x substrate) factors to the growth of catfish (P>0.05). Whereas, for the treatment of stocking densities, a significant difference (P <0.05) was found on four growth parameters (initial weight, SGR, RGRm and feed consumption).

Integration of simple biotechnology practice into conventional feed manufacturing methods is expected to improve the quality of artificial feed. Fermentation technology can be used as an alternative way to increase digestibility or bioavailability of artificial feed. The fermentation agent used is the starter of Lactic Acid Bacteria (LAB), Saccharomyces cerevisiae (Sc) and Rhizopus oligosporus (Ro). This experiment used Completely Randomized Design (CRD) with four treatments (F1; without fermentation agents, F2; BAL, F3; Sc and F4; Ro) and three replications so that the total experimental units were 12 experimental units. The variables measured included the physical and chemical quality of feed, the level of feed consumption and the growth parameters of tilapia. Fermented feed produced significant fish growth (P <0.05) even with the same feed consumption level compared with the control. Breakdown of the nutrient content as a result of the fermentation process causes a far more efficient utilization.