• Looking to buy a cephalopod? Check out Tomh's Cephs Forum, and this post in particular shares important info about our policies as it relates to responsible ceph-keeping.

New & Need Help.

Chef Reef

O. vulgaris
Nov 18, 2007
Hi, everyone, im new to tonmo and came over here for some help with octo questions. i normally am on reefcentral.com but theres not to much info on octo's over there.

I'd like to set up an octo tank and just needed to know all of the basic and some advanced stuff before i do.

This is what i know. Octo's ink, need very good water condition, very secure lid, no holes bigger then its beak, dont like much light, i know what they eat, produce about 3x more ammonia then a fish of equal size. no other fish and corals in the tank. well oxygenated tank. a few other little stuff.

This is what id like to know: What species would be good for a 30 gal tank, for that species would i need a chiller? what temp should the water be at, how to clean up after the octo if it inks, how often to do a water change. More then once a week? How much flow for the tank. is 96 watt PC fixture to much for a 30 gal tank? what all quipment do i need? i think this is it so far..

Thanks for any help i get :)

My quipment list: 30 gal oceanac glass tank, coralife 96watt PC light, skimmer, HOB overflow. i also have air stones and pumps if i need them.
:welcome: to TONMO!

The best place to read up on this stuff is to go to the "ARTICLES" section by clicking that link at the top of the page, and looking at the "ceph care" section.

As an initial note, though, we generally recommend tanks in the 55-75 gallon range for the octos that make the best pets. Many folks are interested in keeping a dwarf octo in a 30 gallon or smaller tank, and often are disappointed in their nocturnal behavior, shyness, and short lifespans. If you're not too attached to this particular tank being your octo habitat, you may want to consider something a bit bigger.
i dont really have room to get a 55 gal tank thats why i was hoping i could use a 30 gal tank that i already have. :/ nocturnal isnt that bad i guess but how short is a short lifespan? im hoping to get at least a year our of one. i looked at ceph care but it only told me what i kinda already knew. :/
Dwarf octos won't live more than a few months, but Dwhatley has had pretty good success keeping a mother Mercatoris, and now her second generation babies are in the process of making another generation of babies themselves. So, since you really want to use the 30 gallon, you might could house a few Mercatoris' in it.
Chef Reef,
Sorry so late in joining in, I have been octo-sitting and website programming until all hours. As Nancy mentioned, if my babies survive - and so far so good - I have happily completed the life cycle with my Mercs. Not unlike other octos, each has its own personality and all five of my original surviving hatchlings (the mother only produced 6 live) act differently enough that a few minutes of observation lets you know who is who. My most active/interactive little guy is Sistrurus and comes out nightly at 10:00 just after the lights go out in the room. He will play with my fingers both inside and outside the tank (I minimize actual touching though) and is almost as interactive (though not clever and is not going to learn to open a jar or even play with the toys I have offerred) as some of the larger species. His tank mate (jury is still out on if Medusa is male of female but I am still thinking female) has learned to be somewhat interactive by observing Sistrurus. She is much more shy but will respond favorably to being "petted" from the outside of the tank. The other three range from being seen one a week (maybe and hence the name, Mia or Missing In Aquarium), to being seen when it wants food and waving its arms around to be noticed at that time but hiding otherwise to taking a den at the front of the tank and not leaving it from the time she was released. The two shy boys are both male and the female in the tank is Miss Broody, the mother of my new borns.

Also, as Nancy mentioned, I have been successful at keeping multiple sibblings (very young non-sibbling groups are likely to work similarly) in a single tank. Others, however, who have tried introducing two adults to a tank have lost both octos. I think that they must be raised together (also evidenced by Zyan's success with the Bimacs). Mine will "attack" each other from time to time but no one is hurt or even inks or panics (so far - now at 8 months). The two in the smaller tank seem to "attack" each other more than in the larger tank but the two roving males may interact more than I see. So far, no one has a skin problem or is missing any limbs and the interaction with Sistrurus and Medusa looks almost like play. I continue to hope it stays this way but only time will tell.

The reputation for a short life span seems to be somewhat overstated. Most octopuses that can live in aquariums have a lifespan of between 12 and 15 months. The Mercs seem be be between 8 and 12 months (judging from Miss Broody's anticipated demise in the coming month) BUT you rarely, if ever, see a wild caught Merc baby, they are just way too small to be by-catch or diver caught or even hitch-hiker noticed. I did not release mine to tanks (from their breeder nets) until they were a full 5 months old.

I have also NOT witnessed ANY cannibalism. Since I have a larger number of babies this time, perhaps this observation will change. My tank bred seem to prefer dead food and it makes me wonder if they are not more of a scavenger in the wild rather than live food consumers (which might explain why my original Merc was caught in a stone crab trap). I have also noted behavior that suggests that they naturally feed on zoo plankton and feed them frozen Cyclop-eeze nightly.

I keep my two most active in a 15 gallon that is just a little too small (I particularly wish it were deeper) and would recommend at least a 20 gallon. I think the three in the 45 have enough room but may not be as interactive because of the size of the tank. All but Mia know that when it is dark and I am at the front of the tank, it is feeding time.

They are strickly nocturnal. If you see a Merc out during the day, I would make a large bet that it has a week or less to live as they seem to do a day walk at the very end of their lives.

I use an outdoor florescent light with a red filter inside the cover that I leave on 24/7 over the 15 gallon (and will probably recreate that setup for the 45 soon) and an LED dome red light 24/7 with white and blue LED during the day over the 45.

If most of my babies survive, I will be looking for homes for some of them in a month or two. Watch the availability thread (and read their journal) if you are interested.
I would be very interested in a few of those babies once you decide to sell. Please keep me in mind. I will be hatching out baby Bimaculoides within the next 2-3 weeks. They will be offspring from a group I purchased from Zyan Silver last September of 2006

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