The Isthmus goby (Arcygobius baliurus) is a species of goby native to marine and brackish waters of the Indian Ocean and the western Pacific Ocean where it can be found at depths of from 3mto15mm (10feetto49feetm). This species lives on substrates consisting of a mix of sand and rubble. This species grows to a length of 10.2cm (04inches) SL. This species is the only known member of its genus.