These bright blue marine crabs are endemic to Bermuda and they're pretty awesome if you ask me. I picked them up on a snorkel collection trip for one of my classes. These crabs are sexually dimorphic in shell selection, the guys use portable shells while the girls stay in tubes made by marine worms. Here's one running around on the lab bench...
This guy happened to get stuck to a rock we brought in for my marine invert zoology class, we were supposed to be looking for worms, I got a bit distracted however, haha.
Those are Dwarf Blue Legs and they are very common, especially in Florida and places around there. I have a caresheet for these guys if your interested.