Hello guys me and my dad want to get a octopus for are tank :D


Sep 26, 2010
Hello my name is mike, And me and my dad would like to get a species of dwarf octopus for are 29 gallon biocube. I understand there very hard to take care of as of right now i have 1 mandarin dragonet goby in my 29 gallon bio cube i have had it running for about 9 months my levels read.

Ph - 8.2

Ammonia - 0

Nitrites - 0

Nitrates - 0

Salinity 1.023 to 1.024 probably about between them

I would also like to now what exactly i have to block off in the bio cube, it has a heavy lid on top covering all holes so i dont think he can get out if i do get one. Let me now guys if u think we can do it please specify what kind of species will be small and not outgrow the tank or atleast not outgrow it very fast. I understand that all octopus species dont live past 6-12months is this correct?
I used to have a 55 gallon reef tank with clowns and tangs for 2 years so i do have experience in saltwater im not a newbie i dont think so tell me what u guys think i allso do not have any corals that can sting him just mushrooms leather corals zoanthids and some star polyps ill probly end up getting aussie corals. :bluering:


Certified Ceph Head For Life
Staff member
Sep 4, 2006
Gainesville, GA
IF you are willing to move the mandarin, your tank setup sounds fine except adding a skimmer is desirable. Large weekly water changes with a good disruption of your bottom substrate will likely compensate enough in a 29 but even a small skimmer is recommended. Areation is also a concern as octopuses need more dissolve oxygen than fish. Adding a skimmer or lowering your water level so that you have air exposure on the returning water is recommended. If you can't accomodate either, adding an active airstone to the sump will help but you will need to filter the bubbles before it returns to the main tank.

If your biocube is an all in one with a sump in the back, you may have issues with the octopus seeking the dark sump as a home. Sponges can be used to discourage this but if it finds a comfortable den in the desired area the sump should be less attractive. Be sure your zoes don't pack much of a sting, some of them can be potent but leathers and star polyps are fine. You will want to push your specific density up to 1.025-1.026, closer to natural sea water.

I would advise against mixing foreign corals in with most any animal as the resistence to disease is unknown.

I have found the the O. mercatoris (the most commonly found dwarfs) often readily take to the large purple barnacles. Clusters can be purchased in various sizes but finding one having several roughly a 1" openings seem to be attactive to the ones I have kept.

Keep in mind that these are nocturnal animals and you will need to add/create a red light if you expect to see them at all. You can keep a pair in a 29 if you can find some that have been caught in the same LR group (ie living close together in the wild). We believe they will live together successfully if they are about the same size even if they have not been introduced but this is not a given. We do know sibblings seem to have no issue living together from at least two captive bred groupings within TONMO.

Here is a loooong post I wrote for another member on keeping an O. mertoris that might offer other ideas or bring more questions.


Sep 26, 2010
ok im going try to keep the manadarin with him he will probly die but im gonna try it out if he likes the sump thats ok he can live in there but i have a big aqua scape so he shuild be able to find a nice den do u now a web site that can sell me a mercatoris octopus?

P.S i have drilled out a small hole with a 1 inch peace of tubing in my stock power head that shoots in my tank its shoot many bubbles into my tank and looks like it should aerate it enough i have seald all the holes on the side off my tank and im going to bring my salinity up to 1.024 will this be high enough and i need to now a site i can buy him at octopuses are hard to find for sale :/


Colossal Squid
Nov 19, 2002
Dunedin, New Zealand
Bubbles are very bad news for octopus, they tend to get into the mantle and kill it. You'll need to figure out some way of preventing them from getting into the main tank

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