Bannerfish

[Lance]

My LFS has a couple of these in. Nice looking. Heniochus diphreutes = (reef safe w/caution), Heniochus acuminatus = (not reef safe). He doesn't know which he has. Invoice only says "Bannerfish". I think they are diphreutes as the last black line ends right at the tip of the anal fin. I'm wondering if anyone has had experience with these fish and what I can expect. How reef safe are they, and what do they like to pick at?
Thanks, Lance