Well, I wrote a long and profound speech and hit the escape key and then lost my connection
so you will get the shortened version. We have a number of articles in the Cephalopod Articles section and the one authored by CaptFish (
Tankmates: It Works Until It Doesn't) should be required reading material for those who want to get adverturous with tankmates.
Ceph keeping is a young hobby (keeping marine tanks is not an old hobby with
Instant Ocean being only slighly more than 50 years old) so we are a long way from knowing all the answers. However, we have a clue about what not to put together in a tank with an octopus if one or the other is not intended as food. We have also learned that
prey and hunter can and do reverse rolls
with size being a major factor. Additionally, numbers matter and
some animals will "pack" to hunt other animals that would otherwise reverse the rolls. IMO an aquarist should strive to provide safer life in the aquarium than it would face in the wild.
Given this goal and the limited knowlege we have acquired, what avoidance rules of thumb are reasonable for the safety of the ceph?
1. Natural preditors (eels, sharks, any meat eaters larger than the octopus or that will grow bigger than the octopus)
2. Animalls that pack or peck (most fish, some shrimp in quantity). Infection being the biggest danger
3. Animals that sting (most soft corals and likely all hard corals) again infection being the biggest concern.
And since we are talking tankmates, what animals are not likely to survive with an octopus but would not harm it?
1. Delicate corals - octopuses do not go around things in their path
2. Natural foods (small crabs, expensive shrimp, decorative clams, small fish)
3. Animals with no self defense (seahorses)
So what is left to try? Anything that does not fit in one of the two lists
. Some of the known animals include:
1. serpent stars (green stars could be a problem but all others have proven successful)
2. brittle stars
3. starfish (I find the thorny to be excellent, there is
antecdotal evidence that the Bahama may be able to trap and kill a small octopus and others that hunt this way might be avoided, common caribbeans are no problem).
4. leather corals
5. mushrooms (not ricordia)
6. low stinging polyps (experimental - advise locating on a removable rock and removing if the octo reacts to touching it)
7. gorgonans placed out of a pathway (note #1 on delicate corals)
8. urchins (pencils are recommended, long spined are out, pin cushions questionable but we have no known problems with them).
I have likely missed some and hopefully others will add suggestions.