Water samples were collected twice daily during the draining and harvesting of three ponds containing channel catfish (Ictalurus punctatus) during January 1992. Samples were analyzed for selected water quality variables. For each tonne of fish produced, an average of 9.2 kg nitrogen, 0.57 kg phosphorous, 22.5 kg biochemical oxygen demand, and 530 kg settleable solids were discharged. Approximate chemical budgets for organic matter, nitrogen, and phosphorous were prepared. Of the organic matter, nitrogen, and phosphorous added in feed, averages of 3.1%, 28.5%, and 7.0%, respectively, were released in effluents; 18.5%, 30.7%, 31.8%, respectively, were removed in fish. Of the nitrogen, phosphorous, and biochemical oxygen demand discharged, 50% was discharged in the last 15–20% of effluent discharged. Of the settleable solids discharged, 50% was released in the last 5% of effluent discharged. These findings suggest that the best way to minimize the pollution potential of aquaculture pond effluents is to harvest ponds as quickly as possible, and either to not discharge water during the seining phase or to discharge this highly contaminated water into a settling basin or retention pond. It also appears feasible to allow effluents to flow untreated into the environment during the preseining phase of draining, because concentrations of potential pollutants are low then.