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How likely is it that a Bimac will try to escape from a tank


May 31, 2003
Just wondering if they'll pretty much try to get out for the sense of adventure or if it tends to be more related to water quality and food.

I've got a small tank raised bimac at my local fish store that I was going to pick up soon. I've been trying to figure out how to go about keeping the little guy in the tank without having to actually close in the top with a big piece of acrylic. Someone told me about astroturf being a good choice of material to line your tank with to prevent them from getting out... I've never kept an Octo before so I'm not sure if it works or if there's something better out there. Also using a hang on protein skimmer presents problems of it's own. How do you prevent the octo from climbing up the return slide from the skimmer or the intake tube to escape for a night on the town? Heaters are another one of the same problems as are powerheads with electrical cords. I'm just trying to be prepaired for any situation and hopefully I won't have to actually put a top on the tank.

Thanks everyone for the input!

Hey Liquid!
To be honest, I have never kept an octo without using a two tank system (drilled and plumbed), so it always had a solid lid on it. I did read a thread a couple of weeks ago re: using astroturf...I have never tried it. The only time the bimacs I have kept really tried to get out was when I had fallen behind in tank maintainance, letting the water quality down, etc...most of the time, they spent playing around the rocks and moving my decorations. One loved to pick up a mushroom coral and move it about the tank...poor coral, never knew where it was going to end up! I think mental stimulation would be good too...check out the thread regarding Ink and her lego block...
Good luck!
Alright, thanks cthulhu. I have a 100gal shark/ray/hostile tank as well as a 140gal reef tank so hopefully my dedication to those two tanks will pay off well with the little octo. If anyone else has any input I'd love to get a couple different opinions, or same ones even :smile:.

Thanks everyone!


I've been trying to track how many bimacs actually try to escape, and I now know of three instances where they did leave the tank (over a couple of years).

Although bimacs are supposed to be less likely to leave the tank than some other species like O. vulgaris, it does happen, and precautions should be taken.

Same concerns here...Gollum never escaped, but he wasn't a bimac, as my next octo will be. I'm leaning toward the "netted-off overflow openings and heavily duct-taped lid gaps" approach. I have heard of bimac escape, rare though it appears to be.

Hey Liquid:

My bimac, Tralfaz, has not (to my knowledge) made an escape attempts. However, I can remember at least one instance here at Tonmo of a member's bimac getting out of a tank (with deadly results). I tend to believe that its better to be safe rather than sorry.

I use duct tape and pieces of acrylic sheet to seal any openings in the hood of my tank. I initially had netting (from a fish net) covering my overflow box. However, I found that it really affected the water flow and quickly became clogged with gunk (There is a molly in the tank which I feed flake food). I removed the netting about a month ago and have not had a problem. I figure that even if Tralfaz made it past the sponge pre-filter in the overflow box he could only make it to the sump although he has shown no inclination to try it yet. :goofysca:

I think that the best policy is to assume that an Octopus will explore any opening that you may leave in the tank. Hope this helps.

OK Cool. I'm not using a big enough tank right now for the octo to be able to really use a SUMP so I won't worry too much about him getting sucked into the skimmer. I'm more worried about the little guy just crawling out of the tank itself. I'll put some astroturf around the edge (inside and out about 2 inches down on both sides just incase he decides to explore my bedroom.

I did finally put him in the tank last night. He seemed very happy to be out of the small cup he had been in at the fish store for about a week. He spent the first hour just crawling around the rocks and eating some bumble bee snails I had thrown in the week before. Then he began digging under a rock which is where he was when I left this morning. He looks healthy and active so I'm not too worried about him. Maybe since he's never known anything but fish tanks (being a raised bimac), he'll feel very content in his little home.

Thanks everyone for your input. Every little bit helps! :smile:

Sorry to have been away for so long :roll:

It was my octo, Sam, that escaped and perished :cry: Serveral things contributed to this. 1) I did have duct tape sealing the tank but never ckd to make sure the salt had not wore it down, thus an open spot. 2) I had another large tank full of fish in the same room, which was the direction Sam was heading. They are very smart and if giving the opportunity they will escape :? Hope this helps someone. :|
Hi Debbie,

Thanks for posting this. It will help others understand that even bimacs can escape.

Did you ever get another bimac?

Escape repellant?

Since salt is so painful on my open wounds, I had wondered if a salt impregnated fabric would be sufficiently discomfortable to octopi and prevent them from escaping? A cotton-type fabric could be siliconed in place and salt-water allowed to evaporate from it. Even if they were sensitive would they manage to avoid contact by looping over it?
Any thoughts?
(I have read of octopus going through fires, maybe they are not sensitive to even life-threatening stimulii they would not normally meet :?: )
Nah, that's asking for trouble... one way or the other, but my guess is that the lion would scran it pretty quick!
Out of over a dozen bimacs I've kept I've only had one escape, and that was well into senescence.

At least eight of those octopuses were kept in a 90 gallon tank with no lid at all.

Tomi Undercoral, my current UberBimac lives in the same 90 gallon tank, and I rarely close the sealed lid. Personally, I've never had a problem with Octopus bimaculoides leaving it's home, but the advice given on this thread is very good- especially with something as sophisticated as an octopus, your own mileage may vary. Better Safe than Sorry.

Oh, and Avoid Cliches like the Plague.

Cheers, Jimbo

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