Research shows that about 25 % of the global fish capture was channelled to the aquafeed production. With an annual positive increment of global fish demand, in a long term, this might be a challenge towards human population as fishes are one of the main protein resources. In this case, microalgae show a promising potential as a substitute resource to replace fish oil and fish meal that was mainly used in the current commercialised aquaculture feed. This is because both marine and freshwater microalgae contain a high composition of lipid, protein, carbohydrates and other high-value products which is essential for fish growth and development. Besides that, microalgae can be culture not only in freshwater but also in marine environment or brackish water. This review focuses on the different types of microalgae and the nutrient content as an alternative resource. The circular bioeconomy and sustainability of microalgae towards social, economy and environmental perspectives were also presented.