My first thought was to look up Octopus sp 18 White V Octopus (norman) based on general coloration, (but missing the white V that should be diagnostic), size and proportions. It was supposed to have been a "Mexican" octopus but I feel quite certain it is Indonesian. My second shot was to look at Octopus abaculus. It mentions white spots I can't identify as being diagnostic and not any of the markings I have noticed. What cirri it has shown so far is branchy but low and limited, unlike Roy's photos. I don't believe it is a young juvenile (IME very young animals are usually translucent) but I would guess it is only 5 - 7 months old (based on inquisitive and active behavior). The mantle is under 2" and the arms at least 6" (which would put it at full grown for my species guess). Unfortunately, I did not take a photo before the bag was opened when I could see the very long arms and it has not fully exposed its arm for photographing since. It does have a rather distinct mantle marking (not always visible) somewhat in the shape of a lobster but not the expected white mark at the end of the mantle for my best guess species. The eyes are very small in proportion to the body, stalky and form a Y like aculeatus. I have seen a single horn on each but I am not sold that it is part of the abdopus family. It can show small spikes all over its body. During acclimation with a white background it showed a gold and green coloration but for several hours it took on deep browns.