Customized medicine on marine ecosystems: The Beneficial Microbes for Marine Organisms (BMMO) network was funded by Raquel Peixoto and Michael Sweet, in 2017, aiming to establish formal and close collaboration between researchers working on the interactions of marine hosts and their associated microbiomes and microbiome manipulation. Our aim is to facilitate the collaborative work between these groups to elucidate different beneficial and pathogenic roles of the microbiome associated with marine organisms, strengthening our efforts towards marine ecosystems protection and restoration, as well as the development of sustainable aquaculture systems.