Diver with remora hitchhiking on his tank.   

The remora followed the diver out of a small grotto and latched onto his tank.

The diver remained oblivious to the passenger.

(Jack's Bight, Utila, Honduras)

fish; remora; sharksucker; Chordata; Osteichthyes; Perciformes; Echeneidae; Echeneis naucrates; diver; tank, Central America