Oncorhynchus masou formosanus, the Formosan landlocked salmon or Taiwanese salmon, is a freshwater salmonid fish endemic to Taiwan. The Formosan landlocked salmon is a subspecies of the more widespread West-Pacific cherry salmon (or masu salmon). This Taiwanese subspecies is critically endangered, being at high risk for extinction, and is protected in its native habitat. The Formosan land-locked salmon is one of the rarest fish in the world. Once a staple of the Taiwanese aborigine diet, there are now barely more than 400 of this type of salmon left. Overfishing has led to its decline. Conservationists are trying to save this subspecies which is threatened nowadays mainly by pollution.