Just a little update. I put the purple tilefish and dusky tilefish in the same tank, a 125 gallon. They are still getting used to the new tank, but so far they seem to just ignore each other. The dusky is more worried about hiding every time he sees someone walk into the room and the stupid tilefish keeps jumping into the overflow. I need to cover it with sometime, because he jumps in at least once a day.