This article presents an analysis of the profitability and intensity of cobia culture by small-scale farmers in Vietnam, especially focusing on current feeding practices and perceptions regarding adoption of manufactured diets. Bioeconomic modelling is used so the interactions between biological and economic processes can be analyzed. Overall, it is found that cobia farming is moderately to highly profitable when compared to other aquaculture species in Vietnam. Culture practices and the level of intensity of cobia farming differ significantly across Vietnam. Initial stocking density, total number of fish stocked, number and size of cages, and quantity of feed used are all higher in southern Vietnam than the north. The higher level of intensification in the south leads to significantly higher total costs, productivity and profitability. The dominant cost source is feed, which is predominantly low-value fish. To capture the environmental and potential economic benefits of adopting pelleted diets, then negative farmer perceptions regarding relatively slow growth rates, and lack of availability compared with low-value fish need to be overcome. © 2014 Copyright Taylor and Francis Group, LLC.