In my opinion, I am going with a Giant Snakehead, aka Redline.....Now, I dont know if it has the strongest jaws or biggest teeth, but it will rip another animal in half no problem with one bite and if it doesnt come apart, it'll shake it like a Pit bull playing tug of war. The wolf fish probably have a stronger bite with equal teeth but they are not very active so I don't know if you would want to waste a 500 gallon tank on a laying monster. Also the Yarelli Catfish, or Devil cat is sick but I think that needs more room.