[tang daddy]

Those don't look like a friendly species, I've seen those breaking off acro branches, any crabs that have a point to the claw is considered dead the only crabs I keep a black gorilla crabs in my tank because they do a good job on algae but sometimes see them eating acros aswell. They don't intensionally go for acros but because they hide and only stick their claw out they have to taste what they eat. Any scrap food gets eaten up by them too which is a bonus....