I have no personal experience with this, but I'll take a wild and unreliable stab at it based on what others have said in other threads. I see purple edges to the suckers and a brownish tinge to the skin. I'm going to guess O. briareus. A picture of the mantle and from the other side would be very helpful, as well as size.
Physical aspects of a male octopus:
- Looking at your first photo note there are several enlarged suckers
- In the second (and you will notice it in the first) you will see a curled up arm. That should be the third arm to the right (clockwise) but the arm positions are difficult to enumerate in the photos (and with Puddles, my octo, all but impossible to determine all the time due to his crazy arm movements).
- color and small frame, arm to mantle ratio about 5:1
- purple lining on suckers (also true of hummelincki/filosus)
- Neogonodactylus (darn it Roy couldn't you have used just Mantis - spelling that kills me) and Muctopus have studied this complex in situ and in lab for years
Additional observations for you to watch for
- A star pattern around the eye
- Little horns to appear over the eyes.
- Wonderful skin Patterning - Muctopus' avitar is another look for this animal. Check out some of her video for this species (try YouTube search huffard aculeatus)
Hmmm, I would make sure there are a few extra feeder crabs / shrimp in the tank and let it play out. He may just still be adjusting to his new surroundings. A few members have used cyclop-eeze when they had octopuses that were brooding and having trouble eating, but I have no experience using it.
Can I twist your arm to start a journal on Mr. Squiggles? An intro on acclimation, any photos you may have taken and where he came from is a nice start and keeping his/her domestic history is helpful for your own memory as well as noting the experience for others.
Alternately, I can move your ID thread to journals and combine with this thread to get it started.