Periophthalmus modestus, the shuttles hoppfish, is a species of mudskippers native to fresh, marine and brackish waters of the northwestern Pacific Ocean from Vietnam to Korea and Japan. This species occurs in muddy estuaries, tidal flats and swamps and marshes and is capable of remaining out of the water for up to 60 hours so long as it is kept moist. This species can reach a length of 10 centimetres (3.9 in) TL.