The Capsalidae is a family of monopisthocotylean monogeneans, which includes about 200 species. The monophyly of the Capsalidae is supported by possession of accessory sclerites in the haptor (the posterior attachment organ), and was confirmed by molecular phylogeny. Their oncomiracidium (the free larva) is distinct from that of other families. Capsalids are parasite on various organs of marine fish (teleosts and elasmobranchs), including skin, fins and gills. Several capsalid species, such a Neobenedenia spp. are pathogenic, especially on maricultured fish.