Can you Explain this hole in MY Pulsing Xenia?

[lucentclownfish]

Here is the sceneario:
Lights were off 24 hours
Temp dropped 2-3 degrees over night
Just added 2 peppermint shrimp.
No other changes
Other living animals
1 fish
1 emrald Crab
1 Banded Shrimp
I can't explain it, it isn't dead but it looks like it is going to be soon.
If you can tell me please do so.
Thanks

 

[beth]

Can't really see a hole. Are there some missing? Probably the shrimp were hungry and ate them. Xenia are pretty hardy. Feed the shrimp real well and place the xenia in a spot where they can get some good circulation.