On my second open water dive in the Philippines, I got attacked by a huge triggerfish. At least, it looked really big. It was my second dive so I didn't know what it was. I felt something tap me on the shoulder fairly firmly. I did a 360 but didn't see any diver close by and then saw a huge fish with its mouth open, teeth exposed and "breathing heavily." It seemed to be huffing and puffing. All of the sudden, it attacked me heading straight for my face. I tried swatting it away and on the fourth swing, made contact with the fish. It bit a piece of my finger off--well, more like nipped the skin. It swam away and faced me again. Another face-off. It attacked me a third time so I started swimming away from it keeping my fins between it and me. I felt my fins make contact with the fish. Finally, the fish stopped attacking me.
My friend who was watching a distance along with a whole 20 other divers who all formed a circle around my karate match with the triggerfish said it looked like a Matrix scene kicking and punching in mid air. Good times.
Now, for some useful info. My dive instructor told me that fish territory is conical and not planar. This means if their territory is 10 square feet at the bottom of the ocean floor, ten feet up it would be more like 50 square feet. I don't know exactly what the proportion but this should give you an idea. I tried swimming up and away when I should have swam down and away.