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The research has been conducted to investigate the impacts of duckweed in maintaining water quality and fish production. Two types of duckweeds (Lemna sp. and Azolla sp.) were used for this experiment consisting three treatments each with three replicates. Ponds under treatment 1 and treatment 2 were covered with Lemna sp. and Azolla sp. Treatment 3 was under control (without duckweed). Comparatively better performance was observed in Lemna sp. than Azolla sp. both in water quality maintenance and growth of fish. Experimental duckweed appeared as nutrient filter for absorption of nitrogen and phosphorus and removed the excessive amount of nutrients from the waterbody and maintained suitable environment for sustainable fish production. On the other hand, uneaten portion of feed and excessive nutrients in treatment 3, led algal blooms that ultimately made the aquatic environment inapt for fish culture and unproductive one.

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