The Chatham deep-water triplefin (Matanui bathytaton) is a species of triplefin blenny in the genus Matanui. It was described by Graham S. Hardy in 1989. This species occurs at depths between 12mand550mm (39feetand1,800feetm) on waters off New Zealand including the Chatham Rise, southeast South Island, Auckland Islands, Antipodes Islands and Stewart Island.