Branchial-parasite
Guides
Elthusa
Elthusa is a genus of cymothoid isopods comprising approximately 40 described species of obligate fish parasites. Species in this genus are characterized by branchial parasitism, attaching to the gill filaments of marine fish hosts where they feed on blood and tissue fluids. The genus has a worldwide distribution with records from the Atlantic, Indian, and Pacific Oceans. Several species have been described from South Africa, New Caledonia, Taiwan, and Japan, with some exhibiting host specificity while others parasitize multiple fish species.