Houdini: O.mercatoris - Itty bitty little fella

Discussion in 'Cephalopod Journals' started by bagarius, Feb 3, 2010.

  1. bagarius

    bagarius Cuttlefish Registered

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    I got a new octopus today. I drove eight hours round trip to pick it up. It was being marketed as a merc, but the shop guy was fairly honest in that he wasn't sure if it was a merc or a baby of something else. It's not afraid of me; its a brave little guy. It's mantle is about 3/8ths of an inch long, and it's arms are about two inches long at best. The best part is that as far as I can tell, it has all eight arms. It may not be afraid of me, but at the same time it's not very social. It will sit there and look at me and fairly ignore me.

    I acclimatized it for two hours with the turkey baster method.

    I've also attached some pics. Hopefully you guys can help me ID this bugger!
     

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  2. bagarius

    bagarius Cuttlefish Registered

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    and picture number 5....
     

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  3. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    I see nothing that would suggest something other than a merc (big eyes, three star like points on the eye, mantle to arm ratio all fit). Once it settles in you will have a better idea. I highly recommend finding a cluster of the large purple barnacles with multiple sized shells. All my mercs have taken these as dens (not always permenant for the males) at some point in their lives, the females have moved to them and not left (but will occassionally switch overnight for what I suspect is an invitation for the clean up crew to clean house as they return the next day). Once situated there is a classic merc pose that is hard to miss if you have a good view. You will see one arm (sometimes two) centered between the eyes and rolled back over the mantle. I have seen others do this once in awhile but mercs take this pose most of their awake den time.
     
  4. bagarius

    bagarius Cuttlefish Registered

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    Thanks! Will it get much bigger? I'll check the fish stores and see if there's any live rock with barnacles on it. One of my pieces of live rock does have some sort of bivalve stuck to it though lol. One final thing, should I take measures to keep this little guy separate from a roughly four inch Atlantic anemone and a coral banded shrimp that I have? My old aculeatus had no problems with them and (amazingly didn't eat the shrimp),but the aculeatus was a heck of a lot bigger; I'm worried this little guy could get hurt, killed or eaten.

    Thanks!
     
  5. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    Wrong kind of barnacle. The barnacles I am referring to are not native for the mercs but they like them anyway. They can be found on eBay , many fish stores and in most novelty stores near the shore (in spite of the fact that they are not native to that beach area).

    I would worry about the anemone but not the shrimp (even though they can be quite agressive about wanting to clean unwilling partrons - Harvey rules my 140 :smile: and scares the trigger half the time). I have seen my flower anemone start to digest my antler that just stumbled across its path (I was able to rescue the antler and moved it to another tank).

    My tank born and tank bred mercs all ended up with mantles between an inch and an inch and a half. The wild caught mother/grandmother was much larger (maybe 2") so like many we see the size can vary considerably but I think you definitely have a baby at 3/8" (I suspect you are under guessing the length though or you have a good macro lens).
     
  6. bagarius

    bagarius Cuttlefish Registered

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    I do have a pretty good macro lens. As you can see, his mantle is a bit smaller than my index finger fingernail. The tupperware tub it's in is right against the outside glass of the tank so you can see it's size well. I see what you mean about the barnacles. That'll be much easier to get ahold of methinks. Good stuff. I just got the anemone from an LFS that I have an incredibly good rapport with, hopefully they'll be willing to take it back.

    Thanks D! As I lurk, your posts are always useful reading. :)
     

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  7. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    My bad, with the finger comparison, you win the size argument hands down. It is very rare to find a WC merc that small.

    I have often said that mercs will not take regular frozen shrimp but Sleazy has made a liar out of me and seems to really enjoy it. One trick, I think, is to cut a piece that is about the size of a shore shrimp in both length and thickness. I have also been very successful with freshly killed shore shrimp from a pipette and, as odd as it may seem, Cyclop-eeze. If you have not seen Gholand's Vary's or My Trapper threads, had a look at them and the photos of the young mercs we were able to bring to adulthood. Greg has the best photos but I compete well on volume. If you have trouble locating them, let me know and I will go link hunting.

    Try to be sure the barnacles have not been coated. Fortunately, most (in not all) of this kind are not. I recomend placing the cluster about midway in the water column and surrounding it with LR. It took Sleazy about a week to move in but I can see her even in the daytime now. Trapper and Miss Broody also stayed visible the rest of their lives after they took the barnacles. My males would move in and out of them but in often enough to make them high on my recommendation list for enjoying a merc.

    If you have not done so, I also recommend setting up a red light and leaving it on 24/7. Mercs seem particularly well adapted to accept even relatively bright red lighting if it never goes completely dark (no so with my experiences with briareus).

    Glad my octo ramblings are helpful.
     
  8. bagarius

    bagarius Cuttlefish Registered

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    Update!

    Before I went to bed last night, I put a hermit in the enclosure with this little guy. When I came out this morning, all I had was an empty shell!
     
  9. bagarius

    bagarius Cuttlefish Registered

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    Update!

    I actually fed this guy today, and it vigorously and aggressively killed and ate an entire ghost shrimp. It's eating really good, and is quite curious. I'm leaning towards it's being a female, but I have no way to know for sure yet.


    edit- it just ate another ghost shrimp. Voracious little thing!

    also, added some pics...
     

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  10. Lmecher

    Lmecher Larger Pacific Striped Octopus Registered

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    Very cute itty bitty litle fella, have your thought about a name? I like the red photos, cool effect 8-)8-)
     
  11. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    Great job on the red light. Unfortunately, you will always have that "cool" effect. My lighting reacts oddly with the camera and a flash and it looks like there is blood at the top of the aquarium in a lot of attempted shots. This camera has a way to correct color by placing a white sheet in the tank and telling the camera that what is sees is white. I finally acquired something to use but have not tried the feature yet.

    As your merc ages, it will not be able to catch the shrimp as easily(that is when I have offered either by hand or at the end of a pipette) but my little guys would go to the basement (the breeder net has a platform) and hunt them at night until they were about 5 months old. I never have had them eat a hermit but other have been successful feeding them, maybe I try the wrong kind. She may also slow down eating once she is fully comfortable in the tank. It appears that octos (like a lot of animals) will nervously overeat until they settle in. I always try to take advantage of this when I acclimate a new one and give them a meal before release.

    Sexing young mercs was a problem for me. I split my first 5 up in groups of two and 3 by the way they interacted. The two that always hung out together were assumed to be a male/female pair and so it appeared for a long time. The most active one (Sisturus) showed enlarged suckers and the curled up arm by 5 months old. His tank mate that I so wanted to be female did not mature for at least another month. Even Sisty thought Medusa was female at one point and tried to mate.

    The other three ended up being 1 female and two males. The female almost immediately returned to her birth barnacle and never gave it up where the two boys would change dens every week or so. Her eventual mate would come visiting every other week and hang out in one of other barnacles attached to the cluster, but not always the same barnacle. The other male (MIA - Missing In Aquarium) stayed mostly to the back of the tank but moved dens.

    Sleazy, my current merc is believed to be female and once she took the barnacle den (about 2 weeks after acclimation) she only leaves it to go to the lower one for an evening so I think denning behavior may be a clue on sexing them.

    I know Roy has worked with this species but has not mentioned denning behavior. We have had very different observations on mating but I think that may be because he keeps his males and females separate accept for short mating opportunities where mine grew up together and lived in a common environment.
     
  12. bagarius

    bagarius Cuttlefish Registered

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    Somehow or another, this little cuss got out if it's critter keeper sometime today. Knew I shoulda kept it in that tupperware bowl. I'm sure it's now denned up somewhere in my big pile of live rocks and I'll probably never see it again. :roll: I am equally sure that my clean up crew is going to start turning up missing LOL

    Oh well, I'll post an update if this dude actually turns back up.
     
  13. bagarius

    bagarius Cuttlefish Registered

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    Well, he turned back up (I've arbitrarily decided that it's male, and that his name is Houdini). I decided to check the tank with my trusty red flashlight last night after all of the lights were off, and he was perched in a clump of fat red star polyps about halfway up the water column. I actually watched him for about an hour, after the lights went out he was VERY active. He even had a scuffle with my coral banded shrimp. Actually I think it was more that they scared each other lol

    I'm happy though that he's not totally MIA though. I hope that he keeps coming out after dark!
     
  14. Lmecher

    Lmecher Larger Pacific Striped Octopus Registered

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  15. Lmecher

    Lmecher Larger Pacific Striped Octopus Registered

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    How's little Houdini doing? Or did he go MIA again :smile:
     
  16. bagarius

    bagarius Cuttlefish Registered

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    I've been doing a lot of watching, but I haven't seen him since the last post. My hermit crab count is inconclusive, the hermits I have are, well, hermity; they tend to hide and don't come out very often. I have so many shells in my tank that new ones aren't immediately obvious.

    I'm getting worried. :/
     
  17. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    I am going to rerecommend putting in a small set of barnacle (maybe twice the diameter of the mantle) and locate them maybe 3" off the bottom positioned so you can seen in but so that the light does not shine directly into the (human) desired den. Even if he is male, he will likely take them for one of his dens. A cluster of varying sizes would be good if you can find one but you can put several cluster in the tank (Sleazy's is embedded in the LR). I don't know why they are attacted to these (possibly the smooth sides) but all of mine have used them for at least part of their lives (they are not native to their home environment).
     
  18. Lmecher

    Lmecher Larger Pacific Striped Octopus Registered

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    D has said it is common for mercs to go into hiding for weeks. It must be difficult wondering if he is alright though. I would worry wether he is eating. Never had that problem w/my O briareus but he is so large even when he is denned up I can see a bit of an arm and he has only refused food a coulpe times in 4 months. I am sure someone with experience will chime in. I am following your journal as well as a few others, quite a few folks with mercs. I am in the process of setting up a tank for a couple. I am learning a lot from all of these experiences. :smile:
     

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