It is interesting to note that fishes form bait balls as a giant defensive formation to intimidate predators but it does not seem to effect tunas, birds, or sharks. I wonder which predators the formation does ward off or perhaps it is just not very effective anymore. The second video provides not only further additional insight on the great underwater food chain but also focuses on some specifics about sharks.
It is amazing how the ecosystems work as seen in the video. The concept of fishes aiding sharks by clearing fungal infections shows how intelligent ecosystems can be. I'm surprised the fishes did not fear becoming dinner and helped the sharks in close proximity instead. Many people also mentioned it must of took the camera man a lot of guts to capture a video that close but I am not sure if that was just an automated video capture or was it done by a live person. If it was done by a live person then that is truly one brave diver doing an extremely wild job working with thousands of sharks.