The mytilid bivalve Fungiacava eilatensis Goreau, Goreau, Neumann & Yonge, 1968, previously mistakenly referred to as F. eilatensis Soot-Ryen, 1969, is reported for the first time from Indonesia. It lives as an obligate endosymbiont of mushroom corals, particulary Fungia spp., reef-dwelling corals restricted to the tropical Indo-Pacific. Notes are given on its association with different host species, its habitat, its biogeography, and its possible competition with endosymbiotic gastropods belonging to the genus Leptoconchus (Coralliophilidae).