Large angels are beautiful to watch, but I think your tank would be pushing it for a queen or a emperor. The annularis, aka blue ring, is on the smaller size of the large angels and it could be possible for that angel to go into a 175. I would make sure not to have any other large swimming fish, like a large tang or something. Another large fish that still might be possilbe would be the ones that don't swim as much, like a grouper or lionfish.