What tank size??

[cbau45]

I know this is a newbie question that probably gets asked a lot but what is an acceptable size tank for an octopus?? I have a 60cube that will be sitting empty as I upgrade my reef to a 150cube. Could I use this tank for an octo? If so, what species would you recommend and how big do they get on average?

-Craig

[CaptFish]

This seems to be a common topic lately maybe we should type up a nice sticky? There are some octos that are acceptable in a 60. I know from Animal Mother that you could get a Abdopus Aculeatus, but I am not quite an expert yet so I'll let someone else chime in.

Now your 150 would be perfect for a O.Briareus




oh yeah

[DWhatley]

A 60 will house any imported Abdopus we commonly see (usually A. aculeatus), the native Caribbean hummelincki and either Pacific bimac species (cold water). The cube shaped does not allow much swimming room and at adult size, briareus would be cramped but they have been successfully kept in a 60 with sump. Briareus is are the largest octo kept in a home aquarium and journaled on TONMO since I arrived. One member thought he had a vulgaris but reviewing the photos indicated Hex was likely a large hummelincki, definately not vulgaris).

[cbau45]

Well thanks for the input. I'll have to do some research on species to see which I like best (and can find around here). The 60 will have a sump and a hefty skimmer. I'll just have to octo-proof the overflow and the top of the tank.

[detherim37]

this is also a newbie question. i am probably going to be told to just go do the research. but which octopus stays the smallest? which one is the most active?

[DWhatley]

CaptFish brings up a good suggestion. I will think about some kind of FAQ for newbies that we can stick at the top of the care thread. It is hard to know where to begin and my thinking is to give some words to the new person for searching (both here an on the net in general). Normally the articles are very helpful with identifying search topics but those won't be available again until around the first of the year.

There are, as you may have guessed more components to choosing an octopus other than activity (least important of any of the criteria) and max size. So rather than answering your question, I will suggest more things to consider.

Species most commonly currently kept in a home aquarium in the United State listed in order of size (largest to smallest):

briareus - Caribbean - crepuscular (hunts early evening, early morning) - large egg
bimac (bimaculoides and bimaculatus) - Pacific - diurnal - large/small egg
hummelincki (also known as filosus) - Caribbean - diurnal - small egg
Adopus (several in complex, most common is aculeatus) - IndoPacific - diurnal - small egg
mercatoris (often missnamed joubini) - Caribbean - nocturnal - large egg

Now that you have some names it should be easy to find out about specific needs, tank size and where to go pick one up. NOT!

The italisized names above list will likely (I'll conservatively guess 70%) contain the species name of octopuses you will see for sale. The other 30% are either rare (wunderpus photogenicus - wonderpus or Thaumoctopus mimicus - mimic - often really a wonderpus when listed as a mimic) and should not be taken from the wild or are dangerous (Hapalochlaena ... any of the blue ring species ) or are in the nocturnal Macropus complex which are fine but just not as common as the others. However, my guess is that 80% of the time you will not see these names listed on-line or in a pet store. Instead you will see, common brown octopus, vulgaris, bali octopus, joubini, Caribbean Octopus (which may or may not be a briareus) or just octopus. In the 20% that give a species name, I am going to suggest that 50% are incorrect. Wholesalers, pet stores and on-line retailers really have no clue on how to identify an octopus. Many retail outlets do not even know from what ocean the animal originated (which is helpful with identity). Even the collectors rarely know what species they are collecting. You might note we have a subforum dedicated to identifying octopuses that members either see in the wild or, more commonly, find in a pet store or have had shipped to them from an online retailer. I suggest reading through some of the requests to get comfortable with the unknown as well as to learn some of the identifying traits.

Another point necessary to begin helping you formulate helpful questions is to understand that the octopuses listed (and most of the others) have natural life spans of 8 months and 2 years, averaging about a year. They are all wild caught and the new hatches are not in the mix (usually too small and too shy to be caught) so age it a crap shoot. The only species that seems to be fairly reliable for guaging age by mantle size is briareus and even that can be iffy.

I make these two points a first priority so that you will consider them when you set up or convert an aquarium with the intent to house an octopus. Allowing a large enough tank for several of the species gives you more flexibility when looking for your first animal and will allow you to change species after it passes through senesence. A 55 gallon tank will accomodate the middle group (65 or better is recommended for briareus and 15-30 for mercatoris). All but the mercatoris should be house singularly.

As to your questions on activity. Now that you have a list of likely animals, look through Forms->Journals and Photos->List of our Octopuses 2008 and List of our Octopuses 2009. The best guess on the species is listed and the entry is linked to the journals for the particular animals. You will see that most will start our shy but all but the mercatoris will become interactive over time. I have noted the diurnal octos (day active) in the list but the crepuscular briareus is also very popular and quite active in the early evening as it ages. The bimacs are high on the desireablity list but have been almost non-existent in the last two years. There are older journals for the bimacs but I have not gone back any further than 2008 to attempt linking the list, however, you can look for the species and the given name for a bimac and use the search engine to find some of the older journals.

After you injest all this, we are readys for your next questions

[detherim37]

the bimac is usually cold water. but it can go up to room temperature right? like around 72 would be a high? m friend has sharks from california and the temps get up to 70 and they are fine. what do you guys think?

[DWhatley]

72 is pretty much the max but we have had several people keep them successfully with 72 as the target max. On the other hand, Dr. Caldwell has had extremely good luck with lowered feeding and cooler temperatures (more than 2 years in captivity). I have not kept one of these even when they were available because I don't like maintaining coldwater tanks (I had coldwater seahorses for several years). Really kind of sad since I actually have a spare chiller that could be serviceable again with a couple of hard to find but inexpensive parts. Maybe one day.

[detherim37]

ok cool. i have a lot of reptiles so my room is warm. if i have a larger tank and dont use a heater the tank should stay cool. or if it gets up to room temperature its not a huge problem.

[detherim37]

if i filled most of my tank with "established" water i wouldnt have to wait the full 3 months right?

[DWhatley]

I would experiment with a tank/bucket of covered water with some lighting and a pump running before you are confident about keeping the tank at 72 or below. Fans can pull the temp down a couple of degrees below ambient but the necessary cover and equipment are likely to be a major issue if your room is above 70. If your room is warm for the reptiles, likely the ambient is above 72 to start.

[bluespotocto]

If you want a good bimac tank get a chiller. I can only say get a chiller. I had a bimac and tried with out a chiller(stupid) the tank stayed around 70f but he never came out. I mean never. I got a chiller set it to 63f and was out a lot more. So save up and invest in a chiller if this is going to be a bimac tank. Also the only known way right now to get a bimac is to go catch one. So if you dont live in CA then you might have a bit of a challenge there. So unless you have a chiller and know how to get one then i would go with getting an aculeatus. They come in quite often at liveaquaria.com. With aculeatus you can put corals and other small fish unlike a bimac tank you cant put a whole lot except an octo.