mine too has also doubled in size in about 2 months, and from that picture mine looks just like that, even know its not a very good picture. i was told my was a vulgaris and that it would only grow to be less than a foot from mantle to arm tip. its already there it seems when its stretched and he still seems pretty young. post some more pictures of close up's or compare to some on my pictures on my "anyone want to try to identify" post