Fish tanks were stocked with 21 Nile tilapia (Oreochromis niloticus) to ripen the system, and 227 blue tilapia (Oreochromis aureus) were stocked for grow-out. For the first year of the study period the fish were fed two different plant based diets: for 9 months a slow sinking feed with 50% protein and for 3-months an expensive and less palatable USDA Organic feed with 32% protein (AquaOrganic diet from The Aquaponics Source). For the second year of the study, a more consistent, commercially available feed was introduced, a slow sinking feed with 35% protein (Finfish Bronze, Ziegler Brothers Inc. Gardners, PA). Fish were fed by hand once or twice a day in quantities based on the number of fish in the system and their body weight and the water temperature, feeding to satiation.