While they are absolutely reef safe and gorgeous, it is very difficult to find a healty one, and very difficult to know if it is healthy. They are VERY sensitive to acclimation issues so, get one from a reputable dealer who can tell you how it was acclimated to their system ( if the answer isn't VERY slowly over the course of hours pass on it), and has had it in their care for several weeks.
Then you need to follow the same slow drip acclimation to your system.
Often they melt away over the course of the 1st few weeks and this is due to improper handling.