Found crab in my new birdnest coral - good or bad?

[shellshocked]

I got a very nice birdnest coral this weekend got it home and today found there were two very small (dime sized) crabs hiding out in the branches. The crabs are the exact color of the coral and even have spots to match the coloration of the polyps. Unless they move you can't see them they blend in perfectly. They have the shape of an emerald crab. Does anyone have any idea if these are harmless? The coral does not appear to be damaged and seems healthy. I can take a picture but they will be very difficult to see.

 

[shellshocked]

I searched the hitchhikers faq and found the crab. It is a commensal(sp?) crab and apparently harmless.

 

[liquid]

Yup, those are definitely cool crabs.

Shane