Biotechnology has immense potential in enhancing animal nutrition, heath-status and productivity. One of such application of biotechnology in aquaculture is probiotics. Probiotics are micro-organisms that are beneficial to host in improving its health, digestive enzyme activity, immunity and nutrition. Probiotics may be administered to fish as a food supplement or as a water additive. These may prove as a boon to aquaculture as these not only improve heath of animal but are also helpful in bioremediation of water, and are eco-friendly. These also compete with the pathogenic bacteria; decrease their virulence, hence, limiting the use of antibiotics. The present review paper highlights the application of probiotics in aquaculture. It also summarizes the development and research highlights of the probiotic status and mode of action, which are of great significance from an eco-friendly and sustainable aquaculture point of view.