Abstract
Ninety-one specimens of the ptereleotrid fish Parioglossus dotui were collected with Callogobius tanegasimae, Luciogobius guttatus, Tridentiger trigonocephalus, Omobranchus punctatus, Thais clavigera, Perna viridis, Ruditapes philippinatum, Hemigrapsus penicillatus and Carcinus aestuarii among tubes of the invasive alien worm, Ficopomatus enigmaticus, from the Sakaigawa River, Kanagawa Prefecture, on 23 July, 2008. Some of them, specifically P. dotui, frequently utilized the inside of tube or the gap among tubes as a shelter for emergencies. The species usually is swimming near colony of F. enigmaticus, rarely observed to escape away from the colony. It was shown that the alien worm provided a new habitat for some native species including P. dotui.
