Preparing for an Octopus Tank


Oct 16, 2012
So, I have been preparing an octo-tank and for months and feel I'm ready to put one in. The species I want is O.Briareus and I'm on a waiting list for one.

Here are my specs.

I have a 72 gallon bowfront that is completely sealed. I am currently running a Fluval 305 canister filter, powerhead, air pump and heater that keeps a pretty consistent 79d. I have a aqua c urchin that I will be running when the octopus gets here.

My water quality seems to be very good aside from all my tests that check great. I've been using tap water as my source for now, I've been considering buying a water distiller. Fortunately Cincinnati has one of the best water filtration systems in the country (so I'm told) and everything in there is doing great.

Here is whats in there. I have a condy anemone, rock anemone, 2 ricordeas, 2 harlequin stars, a brittle star, nudibranch, a turbo, and a flame scallop. As I hear, some of these tankmates aren't suitable. Any advice as what else is suitable or on anything else? Pretty sure I can do some trades on these guys with my LFS.



Certified Ceph Head For Life
Staff member
Sep 4, 2006
Gainesville, GA
At the top of this forum, there are a few "stickies" that address common issues with octopus care. One, now :wink: entitled, Tankmates - What Works and What Doesn't. At entry #10 there is a reposting of one of my long winded lists CaptDave added and is meant to be helpful identifying what you CAN put in a tank.

The serpent and brittle stars are my favorite choice for clean up crew. Most are quite nocturnal (the red brittles are seen more than others for some reason and often "room" with an octopus) but will learn feeding time and show up timely. Most can be hand fed if you choose.

The snail probably has a 50/50 chance of survival. If not eaten in the first 2-3 weeks, it is likely to continue to be a tank helper and you may wish to add several more. I particularly like the astrea snails for algae (but IME, vulgaris loves them for snack, other octos are less inclined to eat them or at least as rapidly).

The flame scallop and nudi have no chance of survival.

The anemones should be removed. You can replace them with leathers and most mushrooms (ricordeas do fall in the low but not no sting category) and sponges (attractive sponges rarely do well in an aquarium, the few I have are volunteer from the live rock and did not show up for several years after the tank was established, there are also sponges that can pollute the tank if they die so read before you buy). Keep in mind that when cnidaria release their nematocysts the little darts go into the water column. The ocean water volume dilutes this quickly but your tank does not have that advantage.


Oct 16, 2012
Thanks for the info. I actually learned this the hard way with the sponge. When I initially added my inverts I also added a beautiful large purple tube sponge. There were some complications with the shipping and everything ended up spending two days in the shipping box. It seemed to be OK when I put it in the tank, but when I came home the next day it was flesh tone instead of purple and had poisoned the tank. It killed two damsels (that I never planned on keeping) that were in there and an urchin. I immediately did a large water change and added bio-boost and things balanced out. So definitely no more sponges.

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