The VACB model has been successfully studied and applied in the Mekong Delta of Vietnam to protect environment and promote sustainable development by recycling energy and excessive nutrients from organic waste. Practically, the effluent from biodigester is collected in earthen fish pond where snakeskin gourami (Trichogaster pectoralis Regan) is raised. To ensure healthy fish growth, pond water has to be exchanged frequently that leads to degradation of aquatic ecosystem due to surplus nutrients, organic compounds and wasting of a substantial amount of surface water. In order to reuse excessive nutrients and purify pond water, the floating beds of water lettuce (Pistia stratiotes L.) at four coverage ratios of 0, 25, 50 and 75 % pond surface area were applied. The higher coverage ratios of water lettuce were studied the better water quality were obtained. Inspire of zero-water exchange in a 60-day study period, the water quality remained within limited range for normal fish growth. In addition, the harvested biomass of water lettuce appeared to be a good supplement of carbon source to biodigester. Results indicated that nutrient recycling and water use efficiency were more pronounced in the integration of water lettuce as floating wetlands in VACB model as compared to the traditional one. Altogether it helps to mitigate negative impact from fish pond towards more sustainability of VACB model.