Crab Question

[sld7530]

We recently purchased this crab from our LFS(about a week ago)
. They suggested he would go great with our tank and is pretty neat.
I have no idea what his name is. Today when we fed him we noticed a HUGE part of his belly has turned black.
Is this normal color changing for him or should I be concerned?

 

[saxman]

Looks like your "he" is a "she"...that appears to be an egg mass.

 

[smallreef]

Free food for your fish!