Missing Mimic Tang x2

[BC Mosaic]

I have an 80g mixed reef with 3 green Chromis and a pair of clowns. About a month ago I got a small 2 1/2" mimic tang and in 4 days it disappeared (no evidence of jumping). Last Thursday I got another mimic tang (2") and today he is missing as well. I also noticed that originally I had 7 hermit crabs (all hitch hikers) and I'm down to one.
Who is the villainous hitchhiker that could be doing this? I'm thinking that maybe I have a monstor bristle star. Or maybe there's a hitchhiker killer crab (I have a few that I haven't been able to catch nor do I see them as much also. Hmmm). It couldn't be the 3 1/2" bristle worm, could it?
This is just too coincidental and how come the chromis and clowns are still around then?
Thanks for any suggestions or tips.
Cheers