Twelve 3 m × 24 m grass strips having two different slopes (3 and 1·5%), two different grasses (Bermuda (Cynodon dactylon (L.) Pers. var. Dactylon) and Bahia (Paspalum notatum Fluegge)) and three replications per treatment were used to filter pond effluent from an intensive catfish (Ictalurus punctatus) production system. The effluent was applied as overland flow at the upper ends of the plots and collected at the bottom as it flowed downslope through the grasses. From two years' data, it was found that the grass strips removed suspended solids in the range of 18–82% from the pond water effluent depending upon the initial amounts of solids. When the initial concentrations of suspended solids in the effluent were above 200 mg L −1, there was a reduction of 62 and 82% of solids owing to grass filtration in 1993 and 1994, respectively. The reduction was about 18% when the initial concentrations of solids were less than 30 mg L −1. The concentrations of chemical oxygen demand (COD) and total Kjeldahl nitrogen (TKN) were significantly lower in the filtered samples (11·8 and 60·8 mg L −1 respectively) than in the applied effluent (17·9 and 77·9 mg L −1 respectively). There was no significant difference between the concentrations of total phosphorus and total ammonia nitrogen in the filtered samples and the applied effluent. This filtering technique may have practical application in reducing nutrient and sediment discharge to receiving waters. It can also become a component of a pond water recirculating system.