Octopus bimaculoides (Bimac) Pickford and McConnaughey, 1949


Dec 22, 2004
I haven't been keeping it very secret that--if the worst has indeed come to pass for Octopets--that I'm interested in obtaining a festoon of eggs.

I would like this thread to become a general discussion of the animal, with particular emphasis on reproduction and aquaculture.

With this in mind I've taken (quite literally actually, but that's another story) some references from the library this afternoon and used them to pass the time until Battlestar Galactica (an episode I was rather pleased with, too). Last year when I moved I threw out a giant stack of Malacologia, which I seriously regret.

I have learned a collosal amount from Forsythe & Hanlon 1998. In the wild, bimacs tend to live in localized, relatively isolated populations. These populations often vary in size: I presume this is why Octopets had said they didn't expect any more Ollies. The study found that bimacs--throughout their lives--seemed pretty tolerant of one another, regardless of study's relatively "overcrowded" conditions. This conflicts with observations from TONMO'ers, however it could be that the study bimacs, hatched in groups of dozens, were better socialized from day one. Also, these octos are kept in containers that simulate their natural environment better than our aquariums do, as I'll mention again below.

The article's description of mating surprised me. The octopus were very promiscuous and showed very little aggression. In many instances, a male octo, happily holed up in its den, would just reach his 3rd arm into a female's adjacent den for a little while, completely sight unseen. Sounds more like Woodstock.

Mean egg size was around 12 mm x 5 mm and they require between 45 and 180 days to develop (a linear relationship with temperature, r^2 = .977!). Hatchlings have very low mortality and will eat mysis and 'pods within 24 hours.

Bimacs were raised in trays measuring ~6 x 2' and 3 x 2' (I am an American citizen and as such I will mix and match metric and standard as I please). Hatchlings were only kept in a couple inches of water, adults not more than 8" or so. Think shallow tidepool and not All-Glass Aquarium!

That's about all I have to say for now. I hope that all of you with experience keeping bimacs or raising octos from eggs chime in. I think we could have a very lively conversation about the best setup in a home for hatching 10-20 eggs rather than 100-200!

Very interesting stuff. I have never kept bimacs, so can only base things on the others, but in reference to the community approach, as long as your tank is big enough, or too small, they will get along fine. Once territory has been established though, look out !
I am sure that with all of the Tonmo people interested in breeding cephs, we will have a steady supply of captive bred animals shortly, probably within a year or two.
Thanks for starting this thread, it should prove to be a great asset to all of those interested in bimacs.

cthulhu77 said:
Thanks for starting this thread, it should prove to be a great asset to all of those interested in bimacs.

Thanks for continuing this thread!

In one of Forsythe and Hanlon's cultures they hatched 44 octopuses in a 0.23 m^2 tray. At three months, they were moved to a 0.72 m^2 tray. After they were a year old, the 38 remaining adults were moved to a 2.2 m^2 tray. Those end-member stocking densities came out to 200 octopuses/m^2 to 13.6 octopuses/m^2!

I'm thinking an amateur hatchery could be made from a large deep plastic tray or pan. A 36 x 24" photographic tray would be ideal, but I'm sure I could find something at a big box retailer that would suffice. Perhaps just the bottom cut off a large rubbermaid. 5 or 6 inches deep with only a couple inches of water. A ring of velcro hooks around the rim might deter escape attempts, although F&H reported virtually none.

It wouldn't need much flow and could be hooked into my existing 75 gallon system. A powerhead in my return chamber would supply water through a clear vinyl tube clipped into the tray. Holes cut in the far side of the tray would empty into an overflow and back into the sump.

cuttlegirl said:
What about a lobster tank (like you see in supermarkets)? They are shallow. I got a used one for $25. It was collecting dust in someone's garage...

Most of the ones I've seen at supermarkets seem pretty deep, more like home aquariums. Not being a lobster eater I have probably missed many, though. The price is right, so I'll keep an eye out. I'm going into the city this afternoon, so I'll look at what kind of things might be had at Home Depot.

The one in Pennsylvania looks perfect for a tank-raising/breeding program like this. However it is quite a bit bigger than anything I could seriously consider now! maybe someday when I have a home and a basement...


I found exactly what I'm looking for at Home Despot this afternoon.

Under Bed Rolling Plastic Box

Internal dimensions are about 19 x 39 x 5". Plenty of room for a couple dozen subadult bimacs!

My LFS is on the hunt, hopefully I should have a quote for a festoon of eggs from a diver in the next week or two.

Even though most of Octopet's merchant account pages have disappeared, Google allows you to view cached pages: a ghost of the page stored on Google's server as it looked the last time they crawled it.

Octopet Egg Festoon

Octopus eggs are difficult, take a lot of time and care to hatch, and once hatched they require live feed. Octopus will not eat dead food until they are older and they do not survive on brine shrimp. I recommend that only the most serious and experienced marine hobbyist attempt to rear an octopus from the egg.

Now If the warning didn’t scare you off, let me tell you how to hatch and care for octopus eggs.

1. Water quality needs to be high, see Octopus info for water quality guidelines.

2. Attach egg festoon to a piece of Styrofoam with fishing line or rubber band, so eggs stay off the bottom and sides of tank.

3. IMPORTANT! KEEP EGGS CLEAN! Gentle aeration under or near eggs, so eggs move just enough to
rub against each other, this helps to keep the eggs clean. Gently rubbing the eggs between your fingers
everyday will also help keep the eggs clean. In nature, the female octopus spends all her time rubbing
every egg of her brood, between 400-700 eggs. She even stops eating and never leaves her
den. Dirty eggs lose the ability to transfer oxygen through the egg wall and will not hatch.

4. Water temperature effects hatch time; the warmer the faster they hatch.

5. The closer to hatching the smaller the yolk sac gets and you will be able to see the baby octopus through
the egg wall. Be very careful with aeration and rubbing eggs when the yolk sac is less than half the size
of the entire egg. When the yolk is the size of a BB (Copper BB gun ammo) or you get any eggs
hatching prematurely, you should stop handling the eggs, premature hatchlings tend not to survive.

6. LIVE FEED! Have your live feed ready for the day the octopus hatch, amphipods , mysids, copepods and
pretty much anything live and small enough for them to handle. Feed 2-3 pods/day/octopus, keep the
area the octopus live as small as possible and as shallow as possible, this helps them catch food because
the food has less space to escape. Always have live food in the octopus tank, so they won’t eat each

7. OCTOPUS DENS, start with ½ inch pvc pipe pieces, always have more dens than you do octopus, so the
octopus don’t fight over them. As the octopus grow and fill their dens you need to put in larger and
larger pipe sizes. They prefer pipes with a cap on one end and half a cap on the other end.

8. The bigger the octopus gets the bigger the live feed, so this gives you more choices for feed. Small
clams, small crabs, snails, worms anything you think the octopus are big enough to catch, eat and won’t
be eaten themselves
I wonder if the eggs would benifit from cylinder tanks at http://www.aquaticeco.com ? With the suggestion of a small air stone bubbling beneath the eggs, a column should do quite well. Hope you have luck with finding eggs. My inital feeling is that they wouldn't be that difficult to find. Fingers crossed!

Thanks for the link, a lot of good specialty stuff there. Most of their tanks are pretty big for what I'm looking to do, though. Even the 25 gallon would be overkill for one festoon a few inches long. I think you're right that a column of some sort would be the best way to go to agitate the eggs, though. Maybe a cylindrical tupperware with the festoon attached toward the top, big enough so there was a couple inches of clearance between the sides and any egg. Regular airstone or a three inch bubble plate (see below) at the bottom.


I could cut a hole in the side for an overflow and set it directly in my hatchery tray, fed by a cheap Aqualifter 3 gph pump. When its time to stop the agitation, I could simply take the festoon out of the column and re-attach it inside the tray.

Hi Dan,

Ha ha! You've got the bug! Advice: Start raising feeders NOW.
Seriously! Stop reading this post and go start rearing greenwater, rotifers, amphipods, mysids and lysmata right now. That way you might be able to handle octo eggs in 6 months or so.

I've been through everything you're talking about. Check out my egg hatching experience here.

later on after that adventure, I used a sweater box as the main rearing chamber for raising cuttlefish with limited success. You need to be very clever with your plumbing fixtures- there's a difficult balance to strike between outflow velocity and escape security. Bimacs aren't escape prone- I've kept dozens of them in tanks without lids for their entire lives. I've never kept them in vessels as shallow as a sweater box though. That might be shallow enough to encourage wandering- they are tidepool octos, afterall. They will explore every nook and cranny available, and could compromise your outflow system. The babies' mantles are only 1-2 mm in diameter, which means they can stroll through the eye of a small needle easily- which amounts to an interesting filtration engineering problem.

GOOD LUCK and ask questions!

Cheers, CephJedi

PS: I've heard the key thing about used Lobster tanks is the built-refrigeration. With chillers starting at $400, a lobster tanks is a cost effective way to keep cold-water species, and some of them approach the sizes necessary to keep GPOs. I've been wanting to find one so I could keep an O. rubescens, but I lack the space for such a monster. I have also heard they can be very tricky to adapt to sensitive species. Lobster tanks were designed to keep lobsters alive for a couple weeks max- their engineering intregrity isn't always up to par for sustaining sensitive creatures for an indeterminate amount of time.
Thanks for the info, Jimbo.

I live about 10 minutes from the ocean so I was hoping to be able to collect amphipods (and maybe even mysis) a couple times a week, and hope to have enough of a stockpile in rubbermaid tubs in case a nor'easter prevented collection for a week or so.

When they get a little bit bigger I was going to turn to some local shellfish aquaculture outfits. I can get baby clams and pea-sized crabs by the bushel for next to nothing.


Trending content

Shop Amazon

Shop Amazon
Shop Amazon; support TONMO!
Shop Amazon
We are a participant in the Amazon Services LLC Associates Program, an affiliate program designed to provide a means for us to earn fees by linking to Amazon and affiliated sites.