Aquaculture continues to grow quicker than other major food production sectors, so optimizing diets is essential in order to create a more profitable and sustainable industry (FAO, 2018). Amino acids are extremely important molecules because of their function in the structure and metabolism of all living organisms. As fish are not able to synthesize several AA, new diets have to provide them with some of these critical nutritional components (NRC, 2011). In order to the fish keep growing and gaining weight, the protein intake needs to be suitable or else the organism could redirect its protein for the maintenance of more vital functions (Lim and Webster, 2002). The aim of this study is to optimize AA balance of the diets offered to tilapia and catfish by examining the role of dispensable AA (DAA) across the range of IAA intakes. The work plan will consist on the elaboration of plant based diets and culture of the specimens in experimental aquariums, which will involve assessing fish mortality and applying dietary treatments daily. Also dissolved oxygen and temperature will be monitored every day. Curde protein in initial and final whole body samples will be tested by the Kjeldhl method (Williams, 1984).