Global population growth and higher incomes are driving increased demand for high-quality, protein-rich foods. Aquaculture is the fastest-growing sector in the animal protein industry, positioned to meet this demand. To make aquaculture sustainable and use renewable, high-protein nutrient sources for animal feed, various strategies are being explored. In this context, single-cell protein (SCP) products offer a promising solution to replace fish protein derived from fishmeal. SCP flours from microbial or algae biomass provide high protein content and sustainable production by utilizing various waste materials. Cultivating microorganisms with waste materials supports sustainable aquaculture protein through single-cell protein, reducing waste. Still, limitations include digestibility, toxin presence, and scaling production in aquaculture. Moreover, single-cell protein has the potential to serve as a valuable solution to meet the global protein demand because of its cost-effectiveness, straightforward production process, and nutritional quality.  The main objective of SCP production is to utilize it as a protein substitute, specifically to combat food scarcity and hunger in the near future.