Mystery wrasse are one of my favorite fish! I purchased one from MvM several years ago, when they were really hard to find. It was one of my "dream" fish. Got him home and in 24hrs....he killed my Scarlett Cleaner Shrimp that I'd had for like 3yrs. :doh:
Then he started nipping at my clams and harrassing my Sunburst Anthias.....:shout:
(He was a model citizen for MvM, a terror for me)
I sold him to a friend that had a FOWLR system and he got along just fine.
This is just my experience with one individual though. Others successfully keep them with inverts in reefs all day long. Just wasn't meant to be for me. Still a gorgeous fish in my book!