Saprolegnia strain was isolated from infected goldfish,Carassius auratus, fingerlings. Fish showed extensive hyphal growth on the skin, fins, gills and eyes. The isolate was molecular identified through 18S rRNA gene and internal transcript spacer, ITS, sequencing. The isolate showed 18S rRNA gene nucleotide identity, 91.6%, and ITS homology with Saprolegnia parasitica. Scanning electron microscopy was applied for evaluating the pathogenicity for the retrieved isolate; which proved its high virulence accompanied with the high mortality rate reaching 100% of the infected fingerlings.