On my 2nd visit to A/C in Jan 2000 I became aware of a shark shaped fish circling me. My dive buddy was off to one side hanging vertically in the water and seemed to be amused. My first impression was that it was a shark - but I had never seen a shark that looked like that.
In order to keep an eye on him I rotated in the water. When he would get ahead of me he would move in closer and I had to reverse direction in order to ward him off. Finally I made a mad dash for my dive buddy and the fish swam off.
I had my Nikonos 15mm set up and snapped a couple of pictures; one of which is on the Hustler Eco Tours web page. I later learned these are sometimes called shark suckers and are similar to Remoras.
When I got on the boat, Ched, the dive master said he was a Cobia and probably a male "As he liked you!”