Flat Symmetric Octopus

This octopus chose to take on the coloration of his background, and flatten himself out. This is the first time that I have seen both eyes of an octopus at the same time. I hadn't know that was possible.

I imagine that octopi can be as symmetric or asymmetric in shape and coloration as they want, and that an asymmetric octopus would be a lot harder to see than a symmetric one. But, they are nearly always just about symmetric in both; and, they are still hard to see. Why? Are there a lot of asymmetric octopi out there, that are too well camouflaged to see at all?