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New to TONMO and to Cephalopods


Aug 13, 2007
Hello all, I recently found your site after doing some research on octopus care. I have been keeping saltwater fish for 10+ years and reef tanks almost as long. Over the past few months I have been researching something a bit more unusual to keep. After ruling out sea horses and mantis shrimp, I decided to try an octo. A bimac. seems to be the obvious first choice. I will explain my planned set up below and would appreciate feedback, corrections or any constructive criticism from the group.


Looking at a 36x18x17 acrylic tank from glasscages. I plan to have the back drilled with 2 holes (1 return, 1 drain) with no overflow. I will use a short standpipe with strainer for the return. The tank will be fitted with full acrylic tops but I will also custom build a fully enclosed canopy.


Prob. be somewhere around 30x12x12. I have a Berlin Turbo skimmer from an old upgrade I will use here. I am also planning a refugium section with LS some LR and chaeto. I will also use this section to house extra live food-shrimps, crabs, etc. Lighting will consist of pc's run about 8hrs a day during the evenings. Mag 7 or so for a return pump.

My concerns:

Lighting: I realize the octo has no special lighting requirements. So would it be possible to have no lighting in the display if the tank is illuminated by ambient light?

Substrate: Is it possible to go bare bottom or is a sand bed pretty much a must?

Clean up: This follows my lighting concerns. The tank will be pretty low flow (water) and most cleanup crews I've seen would end up lunch, so I am concerned about algae outbreaks. Any input here would help greatly.


:welcome: to TONMO!

It sounds like you're on the right track with your thinking. For lighting, I'm pretty sure that you can't really go too dim for the octo to be happy and still be able to see it... even the diurnal octos like bimacs are pretty happy in relatively low light. I'm pretty sure sand is not needed for most octo species, but you might want to wait for others to chime in rather than trusting me on that one, and what choices are good for clean-up crews I should probably leave to more experienced folks, too, but people have found (through trial and error) some clean-up teams that can avoid being lunch some of the time. I think it's sometimes hard to predict in advance, though...
:welcome: My favorite clean-up crew is the serpent starfish. The one in my 47 gal has been through about 10 years worth of octopuses.

My lighting is just a fluorescent cheap bulb and I leave mine on for 24/7. No algae outbreaks and all the octos I have had have adjusted with their own schedule regardless of the lighting.

As far as food, we just put killies, shrimp and some hermits in with Biddle tonight. He did not know what to grab first. It was quite comical! I keep a separate tank also just for food.
With the low light, particularly if you use ambient you will be in love with the glass (acrylic) clean up maintenance! My octo tank is my favorite tank for maintenance since all I ever need to do is stir the sand a little and do a water change (from the sump so the outside doesn't even get drippy). In the year it has been set up, I have cleaned the inside acrylic 3 (maybe 4) times and then only slightly. Compared to my weekly or more often cleanup on the reef tanks, it is heaven. I use a series of LED dome lights for day and a 24/7 dome red (I have a nocturnal dwarf species).

I have found that the red mushrooms can tolerate the low light without starvation but they will look more brown than red and will not become huge (they don't shrink, however). I keep several serpent stars and urchins but the Mercatoris don't seem to care for hermits or snails so they have also survived my first octopus. I kept a small common starfish in the tank for the better part of a year but eventually moved it to a better lit tank fearing she was not getting enough algae to eat. The serpents are meat eaters and will survive nicely on the left-overs. If you keep to ambient light or low light, you will see more of them than in a normal reef.
My understanding is coralline does not need high light levels to thrive and grow. Calcium/alk. are more of a determining factor. I see no reason to elevate Ca levels in this type of set up so I would not think it would be too much of a problem.

Having received no negative feedback on my set up design I proceeded to order my tank from glasscages last night. 36x18x17 eurobraced acrylic with tight fitting lids. Its coming predrilled with bulkheads for my plumbing. Should be here in about 2 weeks.
my first saltwater tank

I have a 55gal marineland 350.
I use diamond blend and one other nitrate remover.
Octo is O. Vulgaris got it in march it was smaller then an oyster and lived in an oyster shell and could hide in it.
Clean-up was a brittel starfish they seemed to be friends till we left a toy octo on desk,he left the starfish right in front of the toy octo with no legs.

So far nothing lives in tank with him for longer than a week except the starfish but is now dead,shrimp seem to be hard for him to catch but he does.

Had algae from running light to long when i frist got him.

My daughter takes the toy along the tank and he attacks it.
Hope that helps


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Is the "diamond blend" your carbon? If so it might switch to straight carbon without the "white diamond" as the white particles in the mix are not for saltwater. Since I knew the product was explicitly NOT for saltwater tanks, I hunted for information on any possible harm. The one site I found said that the "white diamond" substance would be ineffective with any salt (including brackish) but did not indicate that it was harmful.


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