Something in the Macropus complex but different from Puddles and Beldar. The red with the spots makes me think Macropus (along with the reflective green) but the mantle looks too wide to be the same as the SP#10 that the other two resembled (unless it lays eggs very soon)
I found a post brood photo of Bel (where her mantle would have been stretched out) and still think the mantle does not have the same shape. In both animals the mantle was elongated all the time rather than the more rounded appearance of this one. The eyes also look less prominant on this one. There are notes that some may be diurnal but I don't remember which ones (somewhere in Norman in the complex topic though).
Looking at pictures I wonder if this one is actually luteus (pg 249). Look at the larger spots on the webbing below the eyes and the eyes themselves (particularly of the one on 249 vs 248). Also not that little top knot in both pictures as well as in yours.
If the mantle does not show spots, then look at aspilosomatis (244). The extreme arm length seems to be there but the arm patterning looks more regular than the one shot you present . Of the octos I looked at, this one seems to be a close match if it does not present spots on the mantle.