Large Crab Intentification

I recently saw a large crab, about 4" across, maroonish shell, small face, claws were large with black tips. Any guesses on what this is or how compatible it is to a tank?

 

actually, no, the boddy is much larger in comparison to the claws which are shorter and more pug, the walking legs are very cylindrical. I've actually gotten it identified as a Florida Stone Crab. It will eat any snails, oysters, or mollusks in an aquarium but, if anyone is interested in giving it a home or taking it home to eat it (it is caught for it's meat) Petland in Iowa City has it in one of the two lower tanks. It is about fully grown per the information i found.