Just found 2 crabs in my tank

[Kgrizzle]

I just spotted them when feeding my coral and trying to trap the biggest fire worm and I seen a claw come out of a hole in the live rock then while staring some more at the tank I seen another bit of movement and with a flash light low and behold another crab... The first one is buggin me a little cause i think he might have bit my coral but am not sure... Looks like a little chuck smaller than a match head is broken off the edge