Four cymothoid isopods including Anilocra clupei Williams and Williams, 1986, Elthusa sacciger (Richardson, 1909), Rhexanella verrucosa (Schioedte and Meinert, 1883), Mothocya sajori Bruce, 1986, and two unidentified species belonging to Mothocya, that are parasitic on fish, have so far been recorded from the Seto Inland Sea, western Japan (until 2003).