I'm not saying buy the fish, but I know a lot about them and they are not nearly as hard to keep as people think. There are 2 big problems with the fish, neither is due to diet. I have kept several and right now I have a 5 yr old trio, all three were collected by me as juv and now are a male and 2 smaller females. What I have found is that they do not handle drugs well, I used to collect for a living way back when, and drugs especially quinaldine is a legal collecting drug all over the atlantic. They are also found deeper then the other native angels (except for pygmy angels) and they can't be needled, they have to be decompressed. if they were collected better, (we used to use nets only and decompress) they would probably have a much better survival rate. We got great results and had huge demand for our rock beauties for those reasons. The problem is there are way more drug caught fish and once they hit a distributor no one can tell the difference.
I am not saying they are easy, just that if collection methods change we will see a lot more that are successfully kept over a longer period.
By the way I keep mine with a bandit angel, several sp of pygmy angels and butterflies and wrasses. I feed a variety of frozen, referigerated arctipods and spectrum pellets. The tank is chilled and the temp is around 76, I don't heat my tanks. I'm not allowed to collect corals so I only have a few, (sun corals and a blue coral) but I do have lots of octocorals, zoos, and ricordia that I have collected. Also with them are several sp of shrimp. They tend to leave everything alone, though I lose a lot of the smaller shrimp like pedersons cleaners, and sexy shrimp. That doesn't mean that it was the angels, but something tends to eat any that are small.
Another very interseting fact which I have seen in the ocean while diving is that the shy hamlet mimics the rock beauty so it can sneak up on cleaner and other shrimp (its main diet in the wild). The hamlet uses it's color pattern, including a bright blue outlined false eye, to get clost and eat the shrimp.