“…The names thus far given to pathogenic Aphanomyces isolates obtained from diseased fish having epizootic ulcerative syndrome, EUS, i.e., A. piscicida (Hatai, 1980), A. invaderis , and, ultimately, A. invadans reflect individual author preferences, geographic location, and the evolved conclusion that these names actually describe the same organism based on phenotypic and biochemical characteristics, and finally, molecular genotype. The fact that Callinan et al (1995) and Lilley et al (1997) confirmed the same organism as the causative agent of EUS, redspot disease (RSD) in Australia, and mycotic granulomatosis (MG) in Japan, in a variety of fish species would appear to give the name selected by these authors, i.e., A. invadans, primacy. In the most recent World Organisation for Animal Health (Office International des Epizooties former) manual, the 'Case definition' section identifies both names (A. piscicida and A. invadans) as equivalent.…”