You can take the fish out of the ocean...
You can't change their nature. Over time, this fish will eat crabs, snails, etc. It will become very large, and very aggressive, in addition to very messy. I wouldn't even consider it. I hope that you have a very large tank (because you don't want to just pull apart a REEF tank to get this fish out, and it gets huge).
Just read threads on clown triggers. They are not passive little guys. IMO it would be a huge huge huge mistake.