I've been in deep crab observations the last 2 days. So far this is what I've noticed, I have 2 different types of a red crab. One has a couple of white stripes on the legs, and big round claws like the picture above. It also just uses the nets and rarely the big claws. The other crabs have very striped legs, and long straight claws, they have the nets but use their claws mostly, to dig in crevices and such.
I got one of the bigger crabs to come out, and took a picture. Hopefully it is a porcelian, b/c I have at least 4 of these type crabs that a pretty big, and the other type with the straight claw are fairly small so far.
I'll post the picture that I did get tomorrow, if I get time.