Pascal Kobeh / Sicklefin devil ray or Chilean devil ray (Mobula tarapacana) with two shark suckers (Remora remora) Azores, Atlantic Ocean.

David Fleetham / Lemon shark (Negaprion brevirostris) underwater with Remoras (Echeneididae), motion blurred image. West End, Grand Bahama, Bahamas.

David Fleetham / Oceanic whitetip shark (Carcharhinus longimanus) with Pilot fish (Naucrates ductor) and Remora (Echeneididae). In open ocean several miles off The Big Island / Hawaii, Hawaii.

Tony Wu / Humpback whale (Megaptera novaeangliae australis) vocalising with head-down, attended to by Remoras (Echeneidae sp). Vava'u, Tonga, South Pacific.

Linda Pitkin / Whale shark (Rhincodon typus), with remoras (Echeneis naucrates), Mai Mai, between Triton Bay and Kaimana, West Papua, Indonesia

David Fleetham / Remora (Echeneis naucrates) free swimming, Beqa Lagoon, Fiji

David Fleetham / Remora (Echeneis naucrates) free swimming shoal, Beqa Lagoon, Fiji

David Fleetham / Sharksucker (Echeneis naucrates) cleaning scraps from inside mouth of Lemon shark (Negaprion brevirostris), unusual evidence of shark benefiting from relationship. West End, Grand Bahamas, Caribbean.

David Fleetham / Sharksucker (Echeneis naucrates) attached to Lemon shark (Negaprion brevirostris). Grand Bahamas, Caribbean.

David Fleetham / Sharksucker (Echeneis naucrates) feeding on scraps of prey of Lemon shark (Negaprion brevirostris) to which it is attached. Grand Bahamas, Caribbean.

David Fleetham / Sharksucker (Echeneis naucrates) feeding on scraps of prey of Lemon shark (Negaprion brevirostris) to which it is attached. Grand Bahamas, Caribbean.

David Fleetham / Sharksucker (Echeneis naucrates), West End, Grand Bahamas, Caribbean.