What could br nibbling on a montapora?

[Mclendonmdw1]

I recently purchased a montapora frag and now it seems something is nibbling at it. I don’t see any other signs of nibbling on any other corals in the tank, and this is the first montapora frag i have put in the tank. Possible suspects include peppermint shrimp, coral banded shrimp, or possibly a emerald crab. I also have a Clarki Clown and a Sergeant Major in the tank. Any ideas?

The area that has been nibbled on looks half moon in shape.

 

[GTR]

http://www.reeffarmers.com/tracygraynudi01.htm

SteveU

 

[Mclendonmdw1]

Thanks I'm checking for those little pest first thing when i get home.