+1 Cmartin Gorilla crabs are BAD
If it is smooth, you are ok, but I personally dont recommend keeping any of them, as even the smooth colonial crabs still move over the coral causing the acro to retract it's polyps, lessing the time it has to feed. The more the polyp are open,the more it will feed, the healthier it will stay. My opinion.....
I have had to catch and remove a few of the hairy ones they call them gorilla crabs they are bad. If he looks like this one take him out
If it is smooth, you are ok, but I personally dont recommend keeping any of them, as even the smooth colonial crabs still move over the coral causing the acro to retract it's polyps, lessing the time it has to feed. The more the polyp are open,the more it will feed, the healthier it will stay. My opinion.....