Help! Xenia in trouble!
 

Here is the problem:

The xenia are losing all of their "little fingers" (the part that pulses) They look like they are slowly growing back, but I can't figure out why this is happening? Can someone please help me! I have no fish in my tank, only a clean up crew. I suspect there is a pistol shrimp in there due to the large amount (hundreds) of baby shrimp swimming around recently. I dont know what is doing this and I dont want my corals hurting.

P.S.

I have had my xenia in my tank for two months. They are always fully extended and pulsing happily. I have checked all the water parameters and they are all safe.

It sounds like someone in your cleaning crew might be eating your xenia. I had a nice xenia on a piece of live rock in my aquarium and it was very healthy - until bits of it started to disappear. It also looked like it was growing back at one point - but now I cannot find so much as a small piece of it. I am not sure what ate it but I am pretty sure that is what happened.

What can I do to ensure my crew leaves it alone? Should I feed every 2 days?

I feed NLS in my tank every single day - and my xenia still disappeared! In my experience, once something is found to be tasty - it is soon gone!