Hitchhiker Crab ID

[KennyKen]

Is there a database with pictures of various crabs that would hitchhike.

I found this guy in a rock today. First hitchhiker i have found since my tank has been running for 6 monts.

I tried to get a good look at his claws to see if the pincers were flat or not.
He is dark and hairy with red eyes, and his under belly is a much light color.

I tried my best to get him out tonight, i latched onto a pipette, but decided to jump off and scurry away.