Aquaculture is one of the fastest-growing food sectors in Brazil. Cage fish farming has been widely practiced in the country, mainly in hydroelectric reservoirs. However, different regulatory, technical, and economic challenges may need to be overcome before the sector can achieve increased national and international competitiveness. This study aimed to analyze and compare the competitiveness of tilapia cage farms located on different sides of the Canoas I hydroelectric reservoir, which forms the border between the states of São Paulo and Paraná, Brazil. Structured questionnaires were administered to all fish farmers in the reservoir. Questions about seven competitiveness indicators were rated on a 5-point Likert scale. The results revealed that the major barriers to competitiveness are the institutional environment and environmental sustainability. Paraná has an active environmental inspection service, but São Paulo does not. As a result, tilapia fish farmers in Paraná gave more importance to environmental compliance than those located in São Paulo.