The rising costs of high-protein fish feed and inorganic fertilizer have led to increased interest in the utilization of animal manures in aquaculture and in the traditional systems which integrate animal husbandry with aquaculture. This report describes two experiments conducted at the Freshwater Aquaculture Center of Central Luzon State University in the Philippines which indicate that considerable fish production can be obtained when animal manures are properly applied to fish polyculture systems. In the first experiment, 90-day production trials were conducted using 40 or 60 pigs/ha and 750 or 1250 ducks/ha of pond surface, with total fish stocking densities of 10,000 or 20,000/ha. The highest yields - 1,950 kg/ha and 1,690 kg/ha - were obtained using 60 pigs/20,000 fish and 750 ducks/20,000 fish. However, if the market price of fish is size related, maximizing yield may not maximize profits. Comparisons with control ponds receiving inorganic fertilization and measurements of water quality parameters are included. In the second experiment, tropical freshwater fish ponds stocked with 10,000 or 20,000 fish/ha received untreated piggery wastes from 40, 60, 80, 100, 120, or 140 pigs/ha. Based on the two 90-day fish culture periods witnessed during the 180 day pig culture period, the highest net fish yield (3,549 kg/ha) was obtained with 103 pigs/ha and 20,000 fish/ha. When pigs are plentiful and/or pond area is limited, 100 pigs/ha will maximize total revenue and profit; however, when pigs are scarce, 53 pigs/ha will maximize profit for gravity water systems and 67 pigs/ha will do so for pumped water systems. It was also concluded that freshwater fish pond operations are greatly influenced by economies of scale.