Snakehead are you serious? Do you even know what you are talking about? This is a saltwater fish, posted in the saltwater section how is it going to be a hybrid between a brackish cat + columbian shark. It doesn't even look like either!! Some things never cease to amaze me. /facepalm
Definently a type of Scorpionfish. Sailfin Scorpionfish maybe? If so it will get to 4".
It is definitely not a catfish.... dont even know why anyone would think that....
It is most likely a Cockatoo Waspfish, which is closely linked to the scorpionfish slug mentioned, here are a couple of links describing them along with some pics
