It uses its sucker to hitch a ride throughout the ocean...
The diversity of the fish world is almost beyond belief, and among the many bizarre creatures in the sea, there lies a marine hitchhiker called the remora. Nature has endowed this particular fish with a most useful device, a sucker. This adhesive organ, located on its head, enables it to stick to larger fish such as sharks, whales, rays, etc., and even the hulls of ships, as this allows itself to be carried thousands of miles without the slightest effort - hence the marine hitchhiker and/or suckerfish title.
Since remoras lead a mysterious existence within the dim depths of the sea, we know very little about their biology. We do know that they are not parasites because if they were, the sucker wouldn't be merely used for the attachment to a host for travel reasons. In fact, remoras are perfectly capable of swimming and moving about under their own steam, and do so most of the time. Who knows, maybe they just get lazy at times; ha! Some ichthyologists think that the sucking disc, which develops rapidly in the young fish, enables it to migrate in safety - well protected from its enemies as long as it remains attached to the body of some large predator (makes sense to me).
Young remoras sometimes attach themselves to the inside of the mouth or gills of manta rays, eagle rays, swordfish and some sharks (a dangerous creature to choose, if ya ask me). While being attached to these types of marine life, these suckerfish, uh, totally depend on their sucker.
Remoras are sometimes used to catch sea turtles; a line is attached to their tail and when released near a turtle, they immediately batten onto its carapace. From here, all the fisherman has to do is haul in the line, land the turtle, free the remora and start again.
Because of the shape of the jaws, appearance of the sucker, and coloration of the remora, it sometimes appears to be swimming upside down. This probably led to the older common name reversus, although this might also derive from the fact that the remora frequently attaches itself to the tops of manta rays or other fish, so that the remora is upside down while attached.
---End of Post "Remora - Marine Suckerfish"