This study measured aquatic bacteria productivity in the heterotrophic production system of an intensely cultured, high-yielding fish pond using f3HJTdR tracing analysis. Productivity was measured at three different water layers—50 cm, 100 cm and 200 cm below the water surface—and at the sediment surface of the experimental pond. Phytoplankton biomass per day was also measured. Bacterial productivity ranged between 30 and 60 mg/l/day in the water column compared to 114 mg/l/day at the sediment surface, and it was higher at both locations in the evening than in the morning. A rough comparison of bacterial and phytoplankton productivity suggested that bacterial productivity is at least equivalent to, and perhaps 2-3 times higher than phytoplankton productivity.