Extremely aggressive (personal experience). Diver's Den has them from time to time for about $500. They don't require sand, and they are very hardy. If you put them with aggressive fish, you will be okay. Otherwise, I would recommend against it. I had to pull mine out after a short period of time. Although every fish is different, I know other people who have had the same experience.
By the way, I believe that it might be a Opercularis, and Diver's Den will post one this afternoon.