Xenia disappeared/eaten??

[jonrath]

I had a pulsing xenia for the past 3 months and it was doing well and growing nicely.  I just got back from a week of vacation and the xenia is gone, a few small chunks left behind on the rock.  Almost looks like it was eaten.  Any ideas as to what may have eaten it???  COuld it have just died? (although in really looks like it has been eaten, like it was run over by a lawnmower)
My tank is a 90 gallon, Ammonia, nitrates, nitrites all 0 pH 8.2 sg 1.024.  Kh 10, cal 380, Ph 0
Livestock:  2 ocellaris clowns, 1 blue regal tang, 1 royal gramma (the royal gramma is new in the past 2 weeks)
3 cleaner shrimp, 1 fromia star, 1 sand sifting star. 1 porcelain crab.  20 blue leg hermits, 3-4 white leg hermits?, 20 red leg hermits, about 20 various snails ( mexican turbo, astrea, an astrea star snail, cerith, a few nassaurius and 1 crown conch)

It is also possible that I have a red eyed crab that was a hitchhiker. Haven;t seen it in a few weeks, but it was there and I  have not been able to remove it yet.

Thanks for the advice.

[Severum]

I've seen tangs (yellow) eat Xenia before. The blue could be the culprit.

[gerryo]

I have lots of Pulsing Xenia in my tank and would really like it if I could find something to eat some of it.  lol

My Yellow Tang never bothers it.  Mind you, there is enough algea for the tang to eat so it never goes hungry.  It also has had some Swiss Chard to nibble on this past week.

Blue legs never seem to bother anything but themselves.  They're always fighting with each other.

Gerry