I'm a first-time octopus keeper, and I'm having a hard time figuring out what kind of octopus I have here. We got the octopus on Thursday and today is the first day it's ventured out of the live rock to look around the tank. It changes color frequently, and has made a white stripe appear on its mantle occasionally. I was told it was octopus vulgaris, but I'd like to be sure. So far it seems to be adjusting pretty well and has eaten a couple of the hermit crabs we left in the tank for it, but I'm trying to stay ahead of the curve and know as much about it as I can before I run into trouble. Thanks!