This is a shot at 70 ft/21 m. A good place to find neck crabs is on the branching coral at the edge of the wall. Being able to get the back light effect from the surface (I was shooting up) is unusual, but the water was so clear, it was possible. And even though there is not much difference in colour (I was not close enough for that), the crab is still pretty easy to spot, because the coral is closed up (the bushy-looking crab stands out more).