Biofloc technology (BFT) is considered the new “blue revolution” in aquaculture. Such technique is based on in situ microorganism production which plays three major roles: (i) maintenance of water quality, by the uptake of nitrogen compounds generating in situ microbial protein; (ii) nutrition, increasing culture feasibility by reducing feed conversion ratio (FCR) and a decrease of feed costs; and (iii) competition with pathogens. The aggregates (bioflocs) are a rich protein-lipid natural source of food available in situ 24 hours per day due to a complex interaction between organic matter, physical substrate, and large range of microorganisms. This natural productivity plays an important role recycling nutrients and maintaining the water quality. The present chapter will discuss some insights of the role of microorganisms in BFT, main water quality parameters, the importance of the correct carbon-to-nitrogen ratio in the culture media, its calculations, and different types, as well as metagenomics of microorganisms and future perspectives.

Aquaculture has been considered as an option to cope with the world food demand. However, criticisms have arisen around aquaculture, most of them related to the destruction of ecosystems such as mangrove forest to construct aquaculture farms, as well as the environmental impacts of the effluents on the receiving ecosystems. The inherent benefits of aquaculture such as massive food production and economical profits have led the scientific community to seek for diverse strategies to minimize the negative impacts, rather than just prohibiting the activity. Aquaculture is a possible panacea, but at present is also responsible for diverse problems related with the environmental health; however the new strategies proposed during the last decade have proven that it is possible to achieve a sustainable aquaculture, but such strategies should be supported and proclaimed by the different federal environmental agencies from all countries. Additionally there is an urgent need to improve legislation and regulation for aquaculture. Only under such scenario, aquaculture will be a sustainable practice.

Increasing global population and the consequent increase in demand for food are not a new story. Agroindustrial activities such as livestock help meet this demand. Aquaculture arose decades ago and revolutionized the agroindustrial activity as a significant food generator. However, like livestock, aquaculture is based on finite resources and has been accused of being unsustainable. Abandoning aquaculture is not an option considering the food, foreign exchange, and employment it generates, and therefore must be reinvented. Among the many alternatives suggested to make aquaculture more sustainable, microorganisms have been highlighted as a direct food source for cultured fish and crustaceans, a strategy that promises to revolutionize aquaculture by eliminating waste. Considering waste, as part of a cycle, it can increase stock densities and reduce emissions of contaminants and operational costs.

Biofloc culture systems, which are based on the development of microorganisms that recycle inorganic nutrients and organic matter, may contribute to the nutrition of some farmed species. Juvenile red tilapia (Nile Tilapia Oreochromis niloticus × Mozambique Tilapia O. mossambicus) cultured in saltwater were fed pelleted diets in which 0, 33, 67, or 100% of the fish meal was substituted with a vegetable meal mix (corn, wheat, and sorghum meals). The proximate composition of the biofloc produced in the culture systems was evaluated. Four experimental diets and one control diet (isocaloric and isoproteic) were randomly assigned to 15 experimental tanks. Samples of biofloc were periodically collected to measure the total suspended solids, organic matter, and ash content and to determine the protein, lipid, and carbohydrate contents. At the end of the study, variables describing red tilapia production were determined. The biofloc volume, total suspended solids, ash, and organic matter showed significant differences among treatments, but carbohydrate (33.0–39.0%), lipid (2.6–3.5%), and protein (23.7–25.4%) levels were similar. No significant differences were observed in red tilapia survival, final biomass, or feed conversion ratio. We conclude that the substitution of fish meal with vegetable meal in the pelleted feed had no adverse effect on the production response of saltwater‐cultured red tilapia.