I have a German shepherd that gets very vicious to the fish when I hand feed. When I go to get the food from a storage can on our fixed dock, he runs to the edge of the floating dock near where I throw the food and barks, growls, and froths at the mouth until I throw the food in. Then he dives off the dock and tries to eat all the food before the fish can get it. The fish have just learned to feed around him. The other 4 German shepherds just get excited and watch, although one of the females occasionally pushes him into the water before he is ready to dive in. Its all very strange but pretty consistent. I think this male just does not like fish eating what looks like small pellets of dog food. He does not do this with our other dogs and is normally well mannered. He even turns on his heel if called while chasing a varmint.