[Featured]: Octoproofing glass tanks

qiazopus

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Hello all!

Below is an image of an aquarium facility where I'll be carrying out octopus research. I'll be using 12 tanks, each with a mother octopus that will have hatchlings of 4-5mm size.

IMG_9486.jpg


To improve the tanks:
1) I'm looking for ideas of locking devices on the lids on top of adding bricks, since octopuses can be strong enough to lift even weighted lids (also a good idea to prevent anyone from tampering with the octopus if it's a key system or something) I thought of window stoppers but it seems that they require drilling for installation, like what I found here. Does anyone have better suggestions?

2) To separate in-tank devices from the octopus, I'll be ordering some customised perforated plates that look sth like this below. Companies I contacted could only drill holes of 2mm sizes minimum, so I'm thinking of sticking mesh nets on top of it on both sides - what do you think of fly screens or those eco mesh bags in terms of suitable materials (fibreglass, polyethylene?), and ease of tearing by hatchlings?

3) I've the same question regarding mesh but for the outflow pipes that you can see sticking out of the tanks to the floor.
PerfPlate.png


Thank you!!
 

pkilian

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Hi Qiaz! It's nice to see that you are still making progress on this project.

I'm not sure how successfully you will be able to "lock" a glass tank, especially if you are unable to drill holes in the tank. Is the lab space you have not very secure? Is the chance of someone messing with your experiment a high probability? I might not understand the specifics of the space you are in.

One thing you could try in order to secure the lids more firmly, would be to have a velcro strap running over the top of the tank with attachments on either side of the tank, this would prevent the animal from sliding the lid horizontally. If you have enough weight on the lid (~7-10 lbs) you shouldn't have to worry about the octopus lifting the lid upwards, but they will still have enough power to slide the lid to the side, so that's what you should focus on trying to prevent.

I wouldn't worry too much about the hatchlings tearing the screen material. Also, I have used plastic screening in my tanks before and it didn't cause any health issues. I can try and find the specific brand I used in the past but as long as your mesh size is small enough the screen should work perfectly for what you are planning. Additionally, if you are using a mesh in addition to a perforated plate, you can probably have the holes in your plate larger than the diagram shows. With the setup as it is I would worry you may not get enough flow through the perforated plate. The mesh alone will be enough to prevent the hatchlings from escaping, so in theory you don't even need the plate, but it will be good to secure the mesh to something solid. (I would glue the mesh to the plate using coral frag glue, I can link the specific brand I use if you would like, but any should work just fine and cause no issues for the cephs).

For the drains, I would glue the mesh directly to the drain screen if that is allowed. If not, then mesh bags should be suitable as long as they are securely attached to the drain tube with a zip tie or something. What I would use is an aquarium media bag (I can provide a link if you would like). The mesh size should be small enough to prevent hatchlings from escaping. The bags may need to be removed every week or two to be cleaned to prevent the tank from over flowing. You will have to keep an eye on the tanks water levels to make sure you clean the drain screens before the tanks overflow, because the mesh will get dirty and the tank will overfill.

This is an exciting project! Feel free to ask any follow-up or clarifying questions if you have any.
 

qiazopus

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Peter to the rescue again! :biggrin2:

Yes it's a very long planning process haha. Preventing people from accessing the octopus is a bonus but I haven't worked in that facility so I won't know until things happen I guess! The lids from memory do sit on a groove along the tank i.e. it doesn't slide by itself. So maybe velcro + bricks will do the job, thank you!

I was exactly wondering if the holes were too small to allow proper flow, glad that you pointed it out! Yes I was also thinking if it's sufficient to paste a bug mesh screen (link - advertised to prevent small insects) along the walls of the tank and forgo the plate.

I found this glue product - do you reckon this is OK? I've not used one before, does this work while gluing things in the water, or does the object have to be glued outside of water and dried before putting it back in water?

I also found this mesh bag online - what do you think? What's the best way to clean these bags? Are there other precautionary measures I can take when changing the media bag in the presence of possibly hundreds of hatchlings?
 

pkilian

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That mesh screen seems like it would be fine to use. From what I can tell, fiberglass is relatively safe for marine life, much better than a metal screen for sure. The glue looks good to use as well. If it is anything like the other coral glues I have used in the past, it should be okay to use under water, but it cures really quickly (think like 10-15 seconds) so you will have to work fast. Also, I would make sure to let the tanks cycle for a bit after you are done gluing. These are flow-through systems and not recirculating right?

The mesh bag seems like it will be okay to use. If you have the time it could be worth it to buy one as a trial and just make sure that the mesh size is large enough to allow the tank to drain properly. I think your best bet for the mesh bags would be to have one set of dirty ones, and another of clean ones, and then you can swap out a dirty mesh bag with a clean replacement immediately, and then you (hopefully) wouldn't have to worry about losing any hatchlings down the drain. I think the best way to clean the mesh will probably to be to scrub it with a dish brush and/or bleach the mesh. Do you have access to sodium thiosulfate to neutralize the bleach afterward?

Finally, can you remind me what species you are working with again? I have tried co-housing certain species of octopus in the past and their babies usually end up eating each other- they typically don't play well with others. Would this be a potential issue for you? It might be worth thinking of a way to keep the hatchlings separate from each other if necessary for your research.
 

qiazopus

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@tonmo wow that's awesome thanks! Once I get some more logistics done, it should start in June or July! *stressed*

@pkilian
I went to check the hole size of the mesh screen and it's 1mm. The hatchlings will be 4-5mm - does this mean there's a good chance they can escape through it? Even if I get 100micron mesh, there's still the issue of it becoming dirty over time. Yes these are flow-through systems.

I'll be able to order some sodium thiosulfate either in pure anhydrous form or by solution, how many molar do you normally use and is there a particular procedure to follow?

I'm working on the southern keeled octopus (O. berrima) which has hardly been studied. Hatchlings would normally adopt a benthic lifestyle almost immediately upon hatching, although it's not fully studied/established. And yes that's one of the most important questions I wanted to ask - is it even possible to prevent cannibalism?

Also for nocturnal species like berrima, do you reckon it'd be okay for me to use a red head torch to observe them at night? Is it true that LED should not be used? The light for the aquarium room is fluorescent I think.
 

pkilian

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The hatchlings might be able to escape through the 1mm holes, but its hard to know for certain. It's probably better to be safe than sorry, so I would recommend having a mesh as a backup just to make sure they don't escape, then you can have your holes in the plate be a bit larger to allow for more flow through the tank, while not having to worry as much about the animals escaping. How will the dividers be secured in the tank? Will they be removable for cleaning?

To neutralize chlorine from bleach with sodium thiosulfate, you will want to use about 4-5 parts sodium thio to 1 part chlorine. Here is what Syndel's website recommends:
A range of approximately 2 to 7 parts sodium thiosulfate to neutralize one part chlorine is generally suggested, for example: to neutralize 1 liter of a 200 ppm chlorine solution, approximately 0.4 – 1.4 grams of sodium thiosulfate would be required, or to neutralize one gallon of a 200 ppm chlorine solution, approximately 1.5 – 5.3 grams would be required.
As you can see there is a very wide range that will be acceptable. I tend to go a bit on the higher end and then make sure to really soak and rinse my equipment in DI or RO water thoroughly afterwards.

One way you can try and prevent the hatchlings from eating each other would be to keep them separated in a modified bead organizer. If you drill out the bottom of each compartment and glue a piece of screen over the bottom of the organizer, you can allow for flow through the compartments. You might need to fuss with the lid to make sure it is secure enough to prevent the animals from climbing between compartments (using rubber gasket material or something), but I have used these in the past to keep all the hatchlings separated from each other. It is a bit fussy to clean and feed each individual compartment, especially if you will have a lot of hatchlings. Maybe experiment with a clutch or two to see if they will cannibalize each other or not before going through the trouble of setting up the whole bead organizer system.

I think a red LED should be just fine for brief viewings during the night. If you have the budget you could also get an IR flashlight and an IR headset or camera to be able to see the animals without using visible light.
 

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