coral beauty angel

[Maverick00]

Ive had this fish for over a year now but she isnt looking to good these days. Ive noticed part of her tail is missing and one of her fins has a chunk taken out of it. It appears shes still in good spirits and is still eating but swims erratically and looks troubled. The only thing i can think of is she may be getting attacked by the emerald crab i bought to try and control bubble algae a few months ago. Perhaps at night when shes hiding in the rock to sleep? Any ideas? Should i try and catch this emerald crab and throw it in the sump for now?