[Octopus]: New octopus, species unknown

Dec 6, 2009
Herndon, VA
Got an octopus the other day as an "assorted" species and it was small enough to put into a Top Fin 5 gallon all in one aquarium. I have reviewed a few species descriptions but am really not certain as to what species this one is. I do not know where it came from which further complicates identification but it does seem to be a young male that is no more active at night than it is during the day. The octopus can stretch out across the tank but its abdomen is only maybe an inch at most in length when elongated. It's about the size of my 8 year old daughter's last digit on her index finger (and she's very small).

It often exhibits cirri above its eyes and sometimes along its body (pretty interesting as they sometimes look like foraminiferens). It does not have any eye spots that I have been able to see and sometimes seems to exhibit a very slight bluish tinge to the skin, but this may just be a reflection of the light in the room. There is no red coloration that I have seen, either, which leads me to believe that it is not a nocturnal species. More often than not it's a tan coloration except when its eating at which point in time it turns a nice black color. It does not exhibit much if any fear (it has inked 2x out of the blue when we walked up to the tank but if we are there it is more curious than anything else). It does not hide at all but hangs out on top of the rocks or on the glass. It often is up at the top of the water and sometimes sticks its eyes out of the top to take a peek around.

It carries one of its arms curled up for the most part, leading me to believe that this could be a male, but I have not seen a hectocotylus to verify. Suckers on the tentacles are paired and uniform and the arms seem to be fairly rounded, although with such a small octopus this is hard to see. It does not seem to exhibit a very large mantle. I have more or less ruled out Briareus and Joubini, both of which seem to be available through the wholesaler (same as liveaquaria from what I understand) and although it does resemble a few photos I have seen of aspilosomatis it does not resemble the majority of the pictures I have seen.

Some more factors that may help in ID are that it often exhibits raised eyes. It also sometimes has a striped pattern across its body. Honestly, it looks more like a cyanea but I don't think that this is what it is.

Pictures to follow.



Your thread is one reason I am guessing aculeatus. Hoping that this is accurate as this would be a nice small one. It is currently eating a crab that is as big as it is and has eaten pretty much one meal per day of either ghost shrimp, krill, or crab. I have no substrate in the system right now, wondering if I should add a thin layer for its comfort.
Unfortunately, my guess is one of the nocturnal possibly Abdopus (see Epsy) complex (this fits with the importer). Almost every time we hope for a young aculeatus it turns out to be an adult of something smaller that is likely in the same genus. Since this one is showing sexual maturity, my guess is he is one of these "other" sp species. Aculeatus have a pretty substantial webbing. I don't see any on the images you have but it is not always deployed and adds to picture ID confusion (for me atleast). Epsy appeared to be diurnal for the first week or so then disappeared into a hole in the rock and was basically rarely seen again. Epsy may have been female and started to brood so, hopefully, this will not be your experience.

@mucktopus :confused2:
Hey Denise, definitely looks very similar but this one is smaller it seems. If you compared my kids hand to an adult hand it would still be small. Will try and get a video of it on my hand or perhaps a ruler.

Added a bit to the tank for it to eat if it wants. Added 10 margarita snails and also 11 small hermits (assortment of blue, red, and other tiny ones, all potential food or play items). It took a piece of krill the other day but wasn't as interested as it was before so I bought some emerald crabs and it has enjoyed eating those along with making for a far better hunt as it instantly goes after these and hunts them down. Fed it a larger one today with larger claws and it was neat watching it navigate the claws by grabbing them first and then going in for the kill, kind of like putting a full nelson on the crab and then biting its head! Will see if I can find a small jar for it to navigate and earn its crab dinner tomorrow.
Someone was hungry today. Saw it trying to eat a hermit crab so I tossed an emerald crab in and it ate not only ther hermit and the emerald crab while I was gone but then it took down another hermit crab when I got home and kept on picking up the remains of the past two emerald crabs looking for a snack. Getting an order of fiddler crabs tomorrow so that should provide plenty of food for it to be happy (dropped the other emerald crab into some live rock so it is no longer anywhere to be found). Tried to entice it to play today (along with two of my daughters) but it was too hungry to want to do much and basically treated us like we were in the way as it moved by our fingers in the water.

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