In recent years, the expansion of aquaculture area in the Mekong Delta has deteriorated water environment due to high frequency of water exchange while treatment of wastewater from fish pond has not been taken into consideration. Reuse nutrients in fishpond water and use floating wetlands to reduce pollutants in cultured water and to maximize pond area is a new research direction. The floating wetlands with coverage ratios of 0%, 38% and 78% were arranged in intensive striped catfish (Pangasianodon hypophthalmus) tank culture. Tagetes patula L. were grown on the floating wetlands at density of 33 plants/m². The results showed that COD concentration was lower in the higher coverage ratio whereas NH₄-N concentration had an opposite trend. The average concentration of NO₃-N and TP in culture water was not significant difference among the coverage treatments.