I doubt they were coming to the hooked fish's aid. More likely wanted whatever the hooked fish had in it's mouth. I hooked a small pike, 24 inches, in Northern Ontario. It was giving me a decent fight, then it started swimming toward the boat. I had to strip the line in fast to keep up with it. After my buddy netted it and I was taking the fly out, I noticed blood dripping on the deck. The fish was hooked in the mouth. I checked it out and found several large teeth marks and slashes on the back third of the fish. Figured something much bigger, most likely a pike, not only wanted the fly but the fish that was hanging on to it.