The present study was undertaken to determine the ultrastructure of helminth parasite Senga species from freshwater fish Mastacembelusarmatus. The present study deals with the survey of freshwater fishes from Latur District (M. S.) India. This study summarizes the data of freshwater fishes associated with helminth parasites from February 2011 to January 2012. Fish samples were collected from different localities of Latur District. All fishes were examined for the presence of internal helminth parasites in the digestive tract. Scanning electron microscope observations revealed some differences between the present species and other related helminthes detected before.