I just picked up some last Friday.
I've got a 400 G tank and put in two male Square backs and 4 sunburst antheis. So far the two males seem to be hanging out thgether. No fighting between them. AS for the sunburst. They are still hiding in teh rocks, mainly because I have some BIG fish in there and it will just take some time for them to learn that they are harmless. At least it did so far with my other small fish I put in.
Tank inhabitants include 4 large tangs, I'm talking 8 to 13" size. Large Pink tale trigger, 4" bule tang and wantanabei angle, a coupe of small wrasses, 4 royal grammas, and a couple of small Copper banded buterflies.
All seem to get along fine. The 4 royal grammas hid in my rocks for about a week before they became comfortable and realizesd that the big tangs were not going to bother them. Same with the small tang and angle when I put them in.