The oomycete family contains some of the world’s most destructive fish pathogens. In Europe alone, these microorganisms collectively account for multimillion-Euro losses annually in the fish farming industry. Saprolegnia parasitica in particular is a major problem in the aquaculture industry where it has been estimated that 10% of all hatched salmon and eggs succumb to Saprolegniosis. Until 2002, Saprolegnia infections in aquaculture were kept under control with malachite green. However, the use of this chemical has been banned worldwide due to its toxicological effects and this has resulted in a dramatic re-emergence of Saprolegniosis in aquaculture. In order to develop new control practices, we first need to understand the biology of fish-pathogen interactions. Therefore, we need to train scientists in this area of research. We propose to follow an integrated systems biology based approach to study the disease in all aspects: from the molecular level right through to disease management. The overall objective of “SAPRO” is to develop sustainable measures to control and eradicate expanding oomycete diseases that represent a serious threat to aquaculture as well as to natural populations of fish. This goal will be achieved through the creation of an Initial Training Network with 10 early stage researchers and 3 experienced researchers who will be trained in all aspects of state-of-the-art techniques and methods that will be used to study the disease. The program will significantly impact basic understanding of fish-microbe interactions by providing insights into key processes with respect to Saprolegniosis. This research will lead to the development of novel strategies for oomycete disease control that will increase profitability and reduce chemical use in our environment. Lastly, SAPRO has the potential to result in farming healthier fish, which is important for the fish farming industry, the general public, and our environment.