With all things considered, pound for pound it's gotta be the Fahaka Puffer. I've own snakeheads, wolfish, gars, triggers, chichlids of all sorts and after observing all these fish, there is absolutely nothing more fearless then a Fahaka. Fahakas have a bone crushing bite, they are the most creative swimmers and are absolutely relentless. A Fahaka can attack from many different angles and is not limited to head on conflict. As a fail safe the Fahaka tastes terrible to those who bite it and has the added advantage of puffing out if in serious trouble. Fahaka hands down guys.