I'd have thought it would work the other way. Those two should not get allong well, but usually it's the tang chasing the blenny.
However Bristle tooth tangs DO NOT get along with algae grazers that eat "their" algae. Your Blenny might be tougher then the norm, or had delt with a nasty Bristle tooth before. Maybe he's trying to get a leg up before the hunt for himself begins??
P.S. If you'd like to rid yourself of the Blenny, I'd take him. I have no Bristle tooths either. lol