i can not get a pic of him my camra does not have a zoom. He is almost all black with a little bit of white he has the same build of a emrald crab just a little bigger and dose not look like a sally. any help would be great.
Is it brown? If so it might be a close relative of the emerald crab, Mithraculus forceps. Very similar in demeaner to the emerald as well. They don't usually bother any corals, but might grab a fish when it gets a chance. Good luck.
