The fluted kidneyshell Ptychobranchus subtentum (Say, 1825) is a candidate for listing under the Endangered Species Act by the US Fish and Wildlife Service.  Aspects of fish hosts, fecundity, and selected population demographics were determined during 2005-2006 for the fluted kidneyshell in the upper Clinch River, Hancock County, Tennessee.  Females became gravid in mid-August and contained viable glochidia by mid-September.  Eight species of darters (Etheostoma spp. and Percina spp.) were infested in the laboratory to examine potential hosts and host suitability.  Viable juveniles transformed on bluebreast darters (E. camurum) and dusky darters (P. sciera), and previously reported hosts (E. caeruleum and E. flabellare).  In addition, fantail darters and rainbow darters were infested in November, January, and April.  The median time of glochidial metamorphosis was 33 days and did not differ significantly between November and January infestations (median test).  Glochidia were contained in ovisacs that resemble Simuliidae pupae.  Fecundity was positively related to mussel length (r² = 0.94) and ranged from approximately 28,000 to 215,000.  The observed ratio of males to females (1:2) differed significantly from 1:1.  Annual growth of individuals was greatest during the first 3 years of life.