In 1895 he married Carrie C. Williams. The marriage record indicates that both Oliver and Carrie have been married before. So, we don't know if Carrie's birth name is Williams, or if that is her married name from her first marriage.
His marriage record gives his father's first name as "Jacob" rather than James -- did his father go by both? -- Fiscus-32 10:26, 10 September 2015 (EDT)
"United States Census, 1880," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MHSS-ZD8 : accessed 10 September 2015), Oliver S Fiscus in household of James W Fiscus, Jefferson, Owen, Indiana, United States; citing enumeration district 257, sheet 359D, NARA microfilm publication T9 (Washington D.C.: National Archives and Records Administration, n.d.), roll 0303; FHL microfilm 1,254,303.
It may be possible to confirm family relationships with Oliver by comparing test results with other carriers of his ancestors' Y-chromosome or mitochondrial DNA.
However, there are no known yDNA or mtDNA test-takers in his direct paternal or maternal line.
It is likely that these autosomal DNA test-takers will share DNA with Oliver: