Lake Poso (Indonesian: Danau Poso) is a lake in Central Sulawesi, Indonesia, and the third-deepest lake in Indonesia. The lake contains various fish, including the eel Anguilla marmorata which migrates between the lake and the sea, and 11 fish species that are endemic to the lake, notably Adrianichthys, Mugilogobius amadi, M. sarasinorum, Nomorhamphus celebensis, Oryzias nebulosus, O. nigrimas, and O. orthognathus, which are all highly threatened (in some cases possibly already extinct).