Very Small Crab

I was helping out at a local LFS when I noticed a single mushroom getting blown around in the frag tank. I picked it up and a very very very small crab came running out of it onto my hand. I've been trying to get a clear picture of him but I've had no luck. The crab is about the size of a pencil eraser and is tan. To be honest, I can't tell if the claws are pointed or not due to his size, but it does not appear to be hairy. Any ideas what this could be?

 

All crabs start small & grow and there are thousands of species. Without a crisp, well focused image it's impossible to say what it is, sorry.

 

Put it in your sump or fuge to be safe.