Taiwan has limited fresh water resources. Traditional aquaculture industry has a large demand for water. Due to climate change, the Consecutive dry days (CDD) will extend in Taiwan in future. How to use limited freshwater resources is a major issue in aquaculture. This project is aim to establish an ecological farming model for freshwater aquaculture. By using the duckweed to absorb the nitrogen waste, this model can improve the feed nutrient utilization rate and stabilize the water quality in aquaculture pond. Freshwater aquaculture can be a watersaving and environmentally friendly industry by minimizing the overall water utilized for system and waste discharge. Additionally, the photosynthesis of duckweed can capture carbon dioxide from atmosphere in the production process, and convert carbon into sugar for storage, reducing the impact of carbon dioxide on climate change. Present study will investigate the economic feasibility of this ecological farming model. And the amount of carbon storage and functional Ingredients of duckweed will be exam to develop its potential value.