[Octopus]: Davy Jones - O. hummelincki

chipmunkofdoom2

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Hi everyone. New member to the forum, not new to keeping saltwater creatures. I've kept saltwater tanks since 2007. I started working at the National Aquarium in Baltimore a few years ago and fell in love with our GPO Lola (who has sadly passed away recently). Ever since I first interacted with her, I've been determined to keep an octopus of my own. KP Aquatics recently got a few octopuses in stock, so I picked one up. I have no clue what he is though. All I can say is he's from the Caribbean.

He was sold as an "octopus", not a "dwarf octopus." From previous posts, it seemed that the "octopus" KP Aquatics usually sold was a O. Briareus, but this guy doesn't appear to be O. Briareus. He doesn't look as small as some pictures I've seen of O. Joubini, but he's still pretty small. His mantle is probably 2 inches long at the most. I've looked at countless pictures and haven't been able to identify him yet. The most distinct feature he appears to have is a ring underneath his eye on each side that's only visible sometimes. I've attached a few pictures of him at the end of the post. I'd be very appreciative if anyone could offer some insight into what specie he is.

He's in a dedicated 40g breeder and is doing great so far. He took very readily to frozen shrimp, which was a big relief. One of these days I'm going to order some grass shrimp and see if he'll go for those.

At any rate, happy to be here! Thanks for letting me share :)

IMG_20180723_171655.jpg

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tonmo

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#2
wow - nice! And welcome to TONMO!
 

DWhatley

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#3
Grass shrimp will probably be too fast and require more energy than the food provides but are not bad for the tank or for some exercise. Table shrimp are usually the best accepted frozen but you can also offer the occasional clam (keep in a bucket of saltwater for a few hours (add an airstone if overnight and use a high walled bucket as they will squirt the water out of a shallow one). You can leave several clams in the tank to use as minor clean-up crew that may or may not be eaten. ET accepted a piece of raw tuna once but had refused it on a second offering (will offer again at some point). Also raw salmon may be accepted. I have not had good luck with scallops in the past but they are also a valid food. Another live offering that is almost always accepted are fiddler crabs (disable the large pincer on the males, the small one on the male and the two on the females are fine).

I have collected a short list of posts here that are helpful for new keepers and like to recommend reading through all of them. There is a group on food as well as tankmates along with some sexing photos.
 

chipmunkofdoom2

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#4
Thanks for the reply @DWhatley :) I think I read most of the stickies on here in preparation for getting little Davy, but I'll take another look and see if there are any new insights.

Thanks to an ID by DWhatley, I think Davy is O. hummelincki. I took a look at a few other O. hummelincki threads and he looks remarkably similar. I'll continue to post more as things progress.

Here are a few pics I shared in the ID thread of Davy's split arm (#3 clockwise). I'll try to take a few more pictures if I can as I spend more time interacting with him.

IMG_20180725_191342.jpg
IMG_20180726_144253.jpg
 

chipmunkofdoom2

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#5
So little Davy has been odd about his food lately. I typically took a piece of shrimp, thawed it out in my hand, and skewered it on a plastic fork. He would normally come up, feel around on the fork, grab the shrimp (sometimes not let go of the fork...) and happily eat the shrimp.

The past day or so, however, he's been acting a little differently. He comes up to the top of the tank when I bring the food and seems to get a little over-excited. He starts grabbing onto the fork and searching for the shrimp, but seems to be unable to find it. I think he then gets frustrated.. after a minute or so, sometimes finding the shrimp, sometimes not, he squirts some water at me and swims away. As a result, he hasn't been eating a whole lot the past few days.

This morning, I dug out an old testing vial from a Salifert test kit. I rinsed it out really well, added some substrate to make it sink, then put the shrimp on top. Davy sized up the vial for a little bit, did a bit of a color flash, then jetted over and covered it up. I watched him dig his arms in and pull the shrimp out. After he ate his fill, he, jetted back to his rock and settled in his normal spot. We'll see how he likes this routine long-term.

IMG_20180728_131651.jpg
 
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tonmo

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interesting - how often do you feed him?
 

chipmunkofdoom2

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interesting - how often do you feed him?
I've been feeding him daily since the day after I got him. I try to offer him food until he retreats to his cave.

I've been doing some trial and error to feel out how much food he wants. Day one I started by feeding him one ~0.75cm cube of shrimp. Day two I fed two pieces. Day three I fed him four pieces. Day four I fed him six pieces, all of which he ate. Day five he was not so hungry and only ate one piece. Day six he ate three pieces. Since day six, he's been eating 3 - 4 pieces a day.

Today using the plastic cup method, he ate 3 pieces.
 

DWhatley

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Eating habits will change with age as well a how much it ate the day before. When you see lack of interest in food be sure you have not skipped a water change. in stead of assuming senescence. If he does not eat for 2 days, I recommend doing a large water change as he may have inked without you observing it or not doing a water change because the tank cleared quickly (voice of experience), If a water change brings back an appetite, this is likely the reason.

Additionally, I have often mentioned that it takes about a month for an octopus to fully acclimate and we almost always see behavior and eating changes around this time.
 

chipmunkofdoom2

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Eating habits will change with age as well a how much it ate the day before. When you see lack of interest in food be sure you have not skipped a water change. in stead of assuming senescence. If he does not eat for 2 days, I recommend doing a large water change as he may have inked without you observing it or not doing a water change because the tank cleared quickly (voice of experience), If a water change brings back an appetite, this is likely the reason.

Additionally, I have often mentioned that it takes about a month for an octopus to fully acclimate and we almost always see behavior and eating changes around this time.
Thanks, this is really good information. To your point about acclimation, I was actually expecting the whole feeding bit to be more difficult than it has been. He started eating frozen shrimp on day 2, and these pieces are comparatively pretty big. They're much bigger than his eye, which I think I read was the recommended starting food size for frozen foods. I've had tank-bred marine ornamental fish that have been harder to get eating. So I'm definitely ready to adapt to find an feeding method that works for him.

It's also funny you mentioned the inking. I think it was 2 days ago, I was watching Davy explore the tank. He was lazily moving across the front glass when he let out an enormous cloud of thick, stringy ink. I pulled the plug on the pump and started siphoning out the big blobs and did an immediate 25% change (I keep a 44 gallon Brute trashcan of saltwater ready to go at all times). But it was pretty sobering, even acting as quickly as I did, the ink was already disappearing by the time I started siphoning for the water change.

The inking doesn't directly correlate with his loss of appetite, but I was still a bit unsettled by how quickly the ink dissipates. It got me wondering how many times he's inked for no apparent reason and I haven't caught it.
 

DWhatley

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Of all the octopus species I have kept, O. hummelincki inks the most (forgive me if this is redundant :old:). It is almost as if they slowly make ink and have to reduce the volume (probably the wrong guess but there is something different about them). For all but one of the hummelinckis I have, the inking occurs in small releases and often for no apparent reason and without disaster. The one instance where this was not the case the animal completely blackend the tank and the water bucket I removed her to while she was discharging the ink. Once she stopped and I put her in another aquarium (fortunately I had an appropriate tank available) there was never another problem. I had to do a complete water change on the 60 she polluted. I have no clue why it happened. There is a similar incidence with a vulgaris but sadly there was not a spare, unpolluted tank available and the animal died (which may or may not have been a result of the inability to rehouse it).

Et inks more than others I have kept but it is almost always clear that he has been taken by surprise. He stopped eating well for two days and a large water change solved the problem as well has starting a hand feeding success, something he has not done since the first week in the tank.
 

chipmunkofdoom2

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#11
Of all the octopus species I have kept, O. hummelincki inks the most (forgive me if this is redundant :old:). It is almost as if they slowly make ink and have to reduce the volume (probably the wrong guess but there is something different about them). For all but one of the hummelinckis I have, the inking occurs in small releases and often for no apparent reason and without disaster. The one instance where this was not the case the animal completely blackend the tank and the water bucket I removed her to while she was discharging the ink. Once she stopped and I put her in another aquarium (fortunately I had an appropriate tank available) there was never another problem. I had to do a complete water change on the 60 she polluted. I have no clue why it happened. There is a similar incidence with a vulgaris but sadly there was not a spare, unpolluted tank available and the animal died (which may or may not have been a result of the inability to rehouse it).

Et inks more than others I have kept but it is almost always clear that he has been taken by surprise. He stopped eating well for two days and a large water change solved the problem as well has starting a hand feeding success, something he has not done since the first week in the tank.
Wow, ink incontenence. I'll have to watch out for that, thanks. I had never considered this as a possibility. I have a 20g reef tank and a 20g coral QT tank that I could move him to if needed, but it's good to be prepared mentally that this might happen at some point.

So out of curiosity how would I go about moving Davy if he decided to empty all the ink he could into the tank and blacken it? Are there any tricks to enticing him to get into a container? I still have the one KP Aquatics sent him in, I suppose I could always try to get him back into that if needed.
 

DWhatley

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Capturing and moving are nerve wracking but not really all that hard. I think I did a video on one move, let me find it (found the video and thread here). In an emergency, you can't do much about acclimation but most of us will be using the same water and keeping our tanks very close in PH and salinity. If the tanks are notably different and you have the ability to acclimate, it may be a good idea but not for a long period of time like you would for shipping as you will induce stress. The other times I have moved animals to larger tanks, I just ensured the PH and salinity were the same before the move and released them immediately.

Getting the octo into a container (I don't recommend the shipping bottle because it won't hold water and trying to move it quickly will cause more stress all around) is the tricky part, once it is sequestered, the move is pretty simple. The instrument I used in the video was made to move fish and had an air opening along the handle to release pressure. It seemed like a good idea when I bought it but it was really a bit small and there was no way to keep the octopus from getting out other than using my hand. Later moves were done with whatever container I had available that I could cover during the move.
 

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