I don't know if you or anyone else has ideed it yet but it looks like an Atlantic Octopus.One of the most commonly sold cephs in the hobby....at least in this area.It's good to see that it is doing well so far.I've kept them a few years ago and actually have some VHS footage of one of mine from years back.I'd love to share it here but have no clue how I would do that....They are about the coolest aquatic pet that I have ever kept,some of them can be really interactive and I will have another in the future...I think just about any fish you put in there will be in peril,regardless of tank size.When the lights go off and the fish rests,they will be reduced to chum.