Well, since nobody else has said it, I'll just throw in my two cents and say that I don't think you should keep fish to watch them eat other fish. If you want action in the tank, get him a school of 10-12 tiger barbs. Fish that eat fish aren't nessecarily the most exciting to watch, in my opinion. Even muskies, which are one of the largest and most vicious freshwater fish in North America are pretty boring, even in the wild. They just kind of sit there and wait for a meal to pass by, then grab it, swallow it, and sit there until they want to eat again. Most fish won't viciously tear into a school of feeders unless they haven't been getting enough to eat to start with.