No, that round one is a mantis shrimp tank, has no chemical filtration, is only 8 gallons and has a simple air ring for CO2 exchange. It is not suitable for an octo but has worked really well for Fidel, our havanis hitch hicker that came in Cassy's rock last year (we upgraded to a larger tank and brought back some of Ken's LR to add to what we had in the 35 that is now the sump). This one is a hex tank that I use for O.mercatoris (on the glass table in front of the stairs with the 1.5 gallon picos on either side). It won't be suitable for more than a month or two (max) because of the minimized octo proofing but is working better than expected for now (because of what appears to be rapid socialization). You can get a feel for how small she is by looking at the picture of Sleazy sitting in those barnacles in a photo on the first page. Sleazy was an average size mercatoris and I don't expect this one with get much bigger but it will need more room and better octoproofing because of the species.
Initially, I had expected to put this one in the living room corner tank until I saw the size. The corner 45 would be just fine for it long term (I have kept several species in there including three O. mercatoris (together), a macropus and an almost armless briareus) but I prefer to use it for nocturnals and have the diurnal octos in the breakfast room. Most of the ones we have kept in the BR (including three briareus) learn to come out at supper time and we get to see them regularly (Puddles was an exception but the living room tank was taken when she arrived). I have a rectangular tank that might be big enough but I can't remember if it is 25 (too small) or 35 gallons. With some creative plumbing, I would consider using it if it is a 35 and I can rig a 10 gallon sump (we could use the desk that we had been using as a temporary set up for some of the hatchlings as a stand). I have plenty of 10 gallon tanks around but the larger spare is not drilled so we would have to get a drill bit and attempt our first DIY glass drilling if it is the larger of the two. Neal (joking ONLY, Cassy would kill it in a heart beat) suggested putting him in with Cassy to have a 24 hour octo tank. I really DON'T want to have to maintain another tank but this one is already showing acceptance of our presence and I don't want to isolate it from daily activity. Decisions, decisions.
He showed a very strong white stripe while we were watching but we missed getting it with the camera. The red color is not typical hummelincki (he shows a lot of red but it is actually browner than in the photos) and the speckles in the acclimation pictures are not something I have seen before but I am still relatively certain of the species because of the arm to mantle ratio, the eyespot (if you blow up the third one twice you can just make out the bulls-eye ocellus just below the right eye) and the quick taper on the arms (in addition to having had another from the same LR farm). The skunk stripe is something most of them show and is not diagnostic.