Pink Crab?

I bought a pretty big chunk of birdsnest and this guy was inside of it. He comes out at night and roams around, so I had to use the flash on the camera to catch him.





Almost 2" wide when his arms are outstretched like that. Anyone know what it is?

 

Hard to tell, can't see the pincers. Mithrax???


Edit: Check this out...
http://www.chucksaddiction.com/coral_crabs-8.html

 

Looks a little big for a commensal crabs that live in some sps corals. Can you see if he has don't any damage to the tissue on the coral?

 

looks similar to the acropora crabs they sell on live aquaria.

 

i agree with Say,,when i bought a birdsnest coral a while ago,i got one in the coral also.they have some sort of symbiotic relationship with the birdsnest coral.my birdsnest coral died a while ago,the crab just found a new place to dwell,he has not touched /harmed any of my other corals at all.i think he should dot posse a problem.

 

Awesome sight! Crab Hitch Hikers

 

thanks everyone! it does seem to look like the Trapezia/Acropora crab. He just seems to sit in the branches all day. I'll keep an eye on him though