I was once diving near Cabo in Mexico. There was not a lot of coral on that dive, so fish were pretty much what you wanted to look at. We would be swimming along with nothing to see, and then we would run into a school of fish. Then they would be gone and there would be nothing to see. When I realized that they were all moving, I thought, "Hmmm. What if we stayed still?" So we just hung out and, sure enough, we had a steady parade of fish passing by.
That's how many of our dives in the Galapagos were done as well. We saw many hundreds of hammerheads that way.