This octopus is an O. cyanea, also known as the Reef Octopus, the Day Octopus, the Big Blue Octopus, the Big Red Octopus (clear evidence that colour is an unreliable way to classify octopuses!), among others.
However, certain characteristic PATTERNS can help. This species is well known for its very elegant, clean, bilateral colour bifurcations (e.g., black on one side, white on the other). That was my first clue. The second was the shape of the sort of āknobā of flesh around each eye, containing radial striations that i and nearly every ceph biologist tend to call its āeyelashesā. Thirdly, mantle morphology (I just know that shape so well after studying this species for so long) and its apparently extreme adeptness at colour/texture changes. (IME, theyāre the best-camouflaged in the octopus world; indeed, of all creatures except the cuttlefish Sepia latimanus and Sepia apama, to the best of our knowledge.
Anyroad, you have, in my opinion, at least, one of the cleverer octopus species, you will absolutely want to make certain your tank is locked down tight, and that thereās room in that tank for him to grow, as O. cyanea can grow to be a fairly hefty cephalopod, with an arm-span of up to a metre in the wild.
Please keep us updated! Sheās an absolute stunnerāa real beautyāand Iād love to watch him grow and develop. My particular area of interest is ceph communication, and O. cyanea is one of the more expressive occies, along with O. tetricus and O. vulgaris.
