The Gonostomatidae are a family of mesopelagic marine fish, commonly named bristlemouths, lightfishes, or anglemouths. It is a relatively small family, containing only eight known genera and 32 species. However, bristlemouths make up for their lack of diversity with numbers: Cyclothone, with 12 species, is thought to be (along with Vinciguerria), the most abundant vertebrate genus in the world, numbering in the hundreds of trillions to quadrillions.