The Australian Centre for International Agricultural Research (ACIAR) project no. 9130 established causes and control measures for epizootic ulcerative syndrome, a major killer of wild and cultured fish. The project cost $1.7 million dollars and, based on conservative assumptions, could yield net benefits (in present value terms) of $56 million. These significant benefits are a result of the importance of fish production in Australia, Indonesia and Thailand, both as a commercial crop and a source of subsistence income. These benefits are based on the assumption that the knowledge obtained from the project is actually adopted by fish producers and others. There is no guarantee of this, and the results should be interpreted in that light. This also suggests that ACIAR could achieve high leverage from funds devoted to increasing rates of adoption.