The Key silverside (Menidia conchorum) is a species of fish in the Atherinopsidae family. It is endemic to the United States. The Key silverside has been recently recommended for threatened status by the Florida Fish and Wildlife Conservation Commission. The species is a U.S. National Marine Fisheries Service Species of Concern. Species of Concern are those species about which the U.S. Government’s National Oceanic and Atmospheric Administration, National Marine Fisheries Service, has some concerns regarding status and threats, but for which insufficient information is available to indicate a need to list the species under the U.S. Endangered Species Act (ESA).