or sharksucker or suckerfish
Any of 8–10 species of marine fishes (family Echeneidae) noted for attaching themselves to, and riding about on, sharks , other marine animals, and oceangoing ships.
Remoras adhere by means of a flat, oval sucking disk on top of the head. They are thin and dark, 1–3 ft (30–90 cm) long. They live in warm waters worldwide, feeding on the leavings or the external parasites of their hosts.
A remora ( Echeneis naucrates ) and its host, a leopard shark.
Douglas Faulkner