Mine did NOT eat any aptasia. Mine did eat pods and tube worms for months until it started to eat mysis and other raw seafoods. It did not eat any coral.
Mine was small at about 1.5 to 2 inches and the 90G tank could sustain it with live microfauna until it got used to eating in captivity. It is not fat, but it is not skinny. It's little tummy seemed full for the first few weeks while it destroyed all of the tube worms. I see it pick at the sand some too, but I have no idea what it is eating.
I have had it 6 months.
I have never seen one eat the the LFS, but I am sure that some do. I bought this one out of the shipping box in the bag. I have a 75G fuge and a SPS reef full of pods and I wanted to get him/her into those tanks ASAP.
This is one fish that I would caution you NOT to expect success with. You might very well have success, but the odds are not good enough to expect it. If you don't have an established tank with enough microfauna to sustain it (worst case that it never eats prepared foods), then I would say that your odds are pretty poor.