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New octopus need help with I.D


Pygmy Octopus
Dec 20, 2013
Hey guys I'm new to Tonmo.
I've been searching these forums for more than 3 or 4 months now and I finally got my octopus. I had my lfs order it from sea dwelling creatures. Because they do whole sale only. But I talked to their sales rep and he told me they had the atlantic pygmy octopus ( O Joubini ) and also a brown Pacific Ocean octopus but that was the one I didn't want and they told me they would get me the atlantic pygmy. But with the research I've been doing I'm now not sure which species I actually received. I took a few picture that I thought would be helpful any ID tips or hints would be greatly appreciated.
Also he ate the first day and acclimated really well.


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My first thought is that this is an Indonesian (likely Philippines) animal in the Macropus complex ( This is a link Puddles, one of mine in the past, search macropus in journals for additional journals and pictures to compare). If you see white spots on the arms (will not always be present), I'll up my guess percentage 10 points). I looked up the source and they are importers on the West Coast so location fits from what we normally see.

My only hesitation is that I have never seen a clear picture of O. joubini. The animal normally called joubini is not the animal described with that name and has come under the name of O. mercatoris more or less by default (O. joubini is a small egg species where O. mercatoris is large egged but it took many years to distinguish between the two, both are common to the Gulf of Mexico and O. mercatoris somewhat up the Eastern coast). This is definitely NOT O. mercatoris (arms far too long and eyes). It is VERY likely to be nocturnal (eyes and color) and relatively small but not dwarf.

Take care to note that when importers say "Pacific" they are usually talking about Indonesia and NOT the US Pacific coast (US Pacific animals are mostly cold water species and not often collected for resale).
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Thank you for your reply. And I've noticed that he is definitely not nocturnal, he comes out at about 5-6am and stays out and about until about 8-9 pm. I don't have a white light on the tank as I'm using a red led 24-7. I'm not sure if this conflicts with your estimate of o. Mercatoris but I will definitely look into the mercatoris species. If there's anything I can get a picture of to help you determine the species let me know. Thanks for your fast reply I appreciate it very much I want to get the conditions just right for my little guy.
I will bet on a nocturnal. Oddly, we have found that the first week or two will show very different behavior from what you will see after the animal fully acclimates. Nocturnals out during the day is often one of the oddities and in the case of Indonesian animals, keep in mind that day and night are now reversed and its internal clock needs to adjust. The other time we see nocturnals out in daylight is during senescence but this one still has a lot of color so I am guessing (and hoping) that is it not yet that old.

I am sure this is NOT O. mercatoris and more likely an unidentified Macropus species that we see fairly often. Mercs have much shorter arm to mantle ratio and the mantle looks more chubby (almost round).

Here are a few images of some of the macropuses we have in the journals:

And here a collection of O. mercatoris:
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Okay I see. I can definitely tell some resemblance to the first set of photos and the first and last picture of your octos. Is there any general information you can share with me? I was really planning on setting up for a atlantic pygmy so now I'm thinking I might have to go a different route with my tank and set up. What has worked for your octopuses? Any and all tips and information will be much appreciated. And I greatly appreciate your help with ID'ing my new octopus. He really has a taste for fiddler crabs. And ate today and the first day he was with me. Will he be able to be sustained on a crab only diet or should I try and mix in some other fish/shell fish? Thanks again in advance!
My longest Macropus journal will be the one linked to Puddles and should give you a feel for what is most likely this animal but use the search feature (upper right) with the word macropus and check titles only to find some of the others that are journaled (I also kept a female named Beldar but there are several others). There is a video of Puddles on YouTube (and embedded near the end of his journal) where you can see him interact BUT note that I mention the reason I was able to take the video was because he was nearing the end of his life and was out just as the sun came up. He became interactive fairly soon after full acclimation (about a month in the aquarium I think) but chose 3:00 AM for his out and about time. Most of the other "nocturnal" species we keep are more crepuscular and hunt early AM and early PM so there is more time to view them. The macropus that Thales kept and one other (Lennon) at about the same time I had Beldar were out some during the day (Lennon's thread may be a good one to read).

In general, the octopuses we keep can live solely on fiddler crabs but varying the diet seems to be a good idea (some will even get bored with always having the same food and stop eating before they are in full senescence). I would stay with what you are feeding now for a week or two and then try to introduce other foods using a feeding stick. Looking at Lennon's thread, I note the he never acclimated to dead food but that is unusual.

Foods to try (multiple attempts are often required, especially at first - start with an eye sized amounts and increase the size once easily accepted):
  • Thawed grocery store (seafood market even better) shrimp
  • Thawed scallops (warning, don't buy a lot, most of mine have eaten exactly ONE and then not wanted it again but Onn - my current O. briareus - is an exception and age may make a difference).
  • Thawed RAW salmon (be sure to remove any bones) - this is a new winner for me and only offered to Onn but I will add it to my next animal's diet however, fish should NOT be their primary food and never offer freshwater fish.
  • Crab claws from the live bins at an Asian/seafood market (we scavenge the claws that are loose). Be sure there is no odor, they freeze well. Do not freeze a whole uncooked crab
  • Crawdads Live or tails only frozen (again, don't freeze the whole animal as it will be contaminated by the internals). Watch to be sure it is eaten if provided live. Crawdads are freshwater animals and will only live about 1/2 hour in saltwater. Remove if they die uneaten but will likely be welcomed. Because these are freshwater animals, it is thought that they may not provide proper fat ratios for primary feeding so mix them with saltwater foods.
  • Clams offered on the half shell. Any crustacean works but clams are much less of a problem in the tank (oysters are terrible for the tank). More robust animals can open them but this one is not likely to. You can keep live clams in the tank and they will act as a minimal cleanup crew until you want to open it to use one for food (unless you octo opens and eats it). I usually place them in a bucket of tank water overnight before putting them in the tank to let them purge anything they have acquired that may not be good for the tank.
  • Hermit crabs Some people have had luck using them but only my vulgaris (who would eat anything that moved) has eaten them with any consistency (Onn still has the 4 red legs that started with him 9 months ago).
  • Snails will sometimes be eaten but again, I use them as clean up crew and rarely lose any (again except for vulgaris). If you can find some without an operculum, they will be easier for the octopus to extract. We have had one case where the tip of an arm was trapped but I believe the animal was at the end of its life and lacked normal muscle.
  • Shore shrimp can be put in the tank and may or may not be eaten. They will usually be readily taken if impaled on a feeding stick (a trick in itself) or hand fed it you choose to teach it to take food from your hand.
  • Live table shrimp. These are hard to find unless you live near the ocean and hard to transport but it give the octopuses a hunting animal. We try to bring them back from trips to FL and freeze any that don't make the trip but are still fresh.
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Thank you again D for your speedy reply. I will go to my local fish market today and try some of these new food items. I also will be spending my next few days learning as much as I can about this new species ( new to me at least) I'm glad we can almost positively determine what species I have it really helps me to understand and care for this magnificent creature as best I can! And in the end that's what it's all about a happy octopus is a happy octopus keeper! :smile:
I have a new revealing photo of Davey Jones. His color has changed quite a bit! Any ID from this new photo?


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Yes he looks extremely similar to Beldar! Beautiful markings! Do you have a journal on him? Or any tips from keeping that sub species of macropus.
Bel (female) and Puddles (male) were the same species, as are most of the Macropuses we see (the thicker armed animal that Sedna kept may have been different but still in the complex). In the multi-picture collection, the first photo is of Puddles but the second and sixth are of Beldar. I always grin when people are amazed at the different way a single animal can look. After you have kept one, you get a better understanding of why they are so hard to identify and why we ask for multiple photos. If you were to describe the "green sheen" (particularly without photos), the immediate guess would be O. briareus and I mention how much Bel often looked much like O. briareus in her post (see collection post 2 photo picture #5 in Zigzag's new briareus journal).
Great read! Thanks for sharing! Davey Jones is doing great! He loves his fiddler crabs! Didn't seem interested in eating any of the shrimp and clams I bought from the fish market.. But he is such an amazing little critter!
Keep trying with the other foods. Offer something else once a week or so. Age and becoming accustomed to being fed as well as preference impact what they will and won't eat. Clams can be kept live right in the tank and anything else can be cut into feeding size and frozen for future attempts. For years I swore O. mercatoris would not eat table shrimp only to be embarrassed by my last one.

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