Aquaculture is increasingly to grow fish for food, repopulation, and other necessities. Maintaining high-quality fish while saving on resources and expenses is key for both farmers and consumers. Our study, which used Red Belly Pacu fish, focused on the effectiveness of utilizing duckweed as part of the feed and as a reducer of pollutants in the tanks. This study’s goal was to see if we can use this alternative to reduce the cost of fish feed without having detrimental effects on fish growth, as well as provide possible benefits in terms of tank cleanliness. The model comprises 4 tanks, each with varying amounts of duckweed (both for feeding and filtering purposes). Over 2 years, we measured fish weight, water temperature, and water quality parameters such as pH, nitrite levels, and ammonia levels. After analyzing the data with fixed effects and random effects models, we concluded that if up to 40% of the total fish feed is replaced with duckweed, fish growth will not be harmed. Although more studies must confirm lower pollutant levels in tanks due to duckweed, our study showed some indication that this was true. If our model of using up to 40% duckweed in tanks is followed, farmers can be expected to save about 15-20% in production costs while maintaining the same quality of fish.