Invisible Bimac


New member
I'm really getting discouraged. I got a bimac from ffe 8/12. For the first few days he was all over the tank. For the next week, he was out occassionally. In the last month, I've seen him twice, and one of those times was cause I moved all the rocks in the tank until I found him! The other time was when I came down for some Tylonal at 3:00 am, but he hid as soon as the light came on. I put food in the tank, and it turns up the next morning (mostly) eaten. Live ghost shrimp and frozen krill. He also ate some red leg hermits (after several days), but he completely ignores the snails I put in the tank. I think he's gotten a little bigger from the two glimpses I have had, but it's hard to say.

Is this typical of octopi and bimacs in particular? Why have a pet that requires expensive live food if you never see it? Will it get better as it gets older? I'd feed it frozen food, if I could find it, but just putting the food on the bottom doesn't work--it ends up in the filter or eaten by the snails and starfish. Seems a shame to set up a whole tank for an animal that's never out. Does anyone have any advice?

Seriously discouraged,

Jim Jensen
I just got a bimac for the shop from chris on Sunday. He's been hiding 99% of the time but comes out occasionally, I've been training him to take food from some tongs or feeding stick as opposed to leaving food for him. Maybe you should give that a try - try to figure out where his favorite lair is and thin out the food population in there and try to feed by hand (or stick). This should develop a relationship with you as the food god and he'll be more likely to come out when hungry.

least thats how chris explained it to me and it seems to be working with ours he's slowly becoming social.
Hi Jim

Sorry to see that you are so discouraged. I would like to offer support in saying that your bimac is just a baby and will eventually start to behave differently when it grows a bit bigger.

Imagine that this octopus was in the wild.... it is so small, has no hard shell, isn't poisonous or venemous and still knows very little about its habitat around it..... so what does it have????

Well, it has the skill to change colour, change texture and luckily for it, fit into tiny spaces. A baby octopus of any species has to hide to protect itself. Otherwise, in the harsh marine ecosystem it is something elses dinner!

So, in my experience, when cephs grow older and become more acustomed to their environment and to you, they will start to see you and others around them as part of the scenery that doesnt hurt them. BUT this all takes time!

It is very easy for us in this modern day world of instant gratification to get ****ed off at not getting what we want when we want it! Well, for me, part of the appeal of octopuses is that this is on their terms too. I have learned a lot from watching them... If I wanted something swimming about all day I would buy a goldfish. But you, like others were drawn to the mystery and wonder of the octopus, not the humble and 'brainless' goldfish.

What have you offered your octopus into stimulating it? What sort of environment have you given it? Is it a bland lifeless tank? Is it full of rocks and pipes and algae and things to explore? Does it feel safe in your tank?

Octopuses and other cephalopods require very specific and exact conditions to thrive. Not just perfect water and filtration but an environment that suits such a 'smart' creature.

If he's eating he's doing fine but you have only had it a little over a month. Give it a chance.

Seems a shame to set up a whole tank for and animal that's never out.

Well, that's octopuses for you, it comes with the teritory. They are not the ideal pet for everyone.

I hope you stick with it as the rewards are really worth it...

heheh, sounds like my first octopus experience. She was strictly nocturnal. I never saw her in the light.

You said one of the two times you saw your octopus was at night but it hid when the light was turned on. Try this: buy a small fluorescent light and paint the bulb red. That worked for me and I was able to watch my octopus move around at night sometimes, without turning on a bright light and scaring it.

I fed her with a piece of shrimp on a string. I just hung it outside her cave at night and an hour after the lights went off (and red light came on) she would come out and get the food. I never got a really good view of her but was still able to enjoy it. I would wake up in the morning to find she had dragged a large shell across the tank to her cave and use it as a door.

How did you paint the bulb red??? What paint?? I was thinking red cellophane over the bulb which might be easier. We used to have a big bimac at school that was completely social. Anytime you lifted the lid of the tank he would come and try to pull you in. This is why I bought mine, but he's very much the opposite, very nocturnal as described above. It's only been a week, though, I guess you just have to be very patient. I'm going to try not feeding him for a few days and see if that stimulates him to take a hand feeding.
good question, im not sure what kind of paint. It was only flourecent lights so they dont get hot, im not sure if it matters. Although after the light was on for a while it did emit a little paint smell. Red cellephane would be better, you can buy light bulb covers like that at most fish stores.
I've had the exact same experience. Check out some of my other posts on this forum. If you want more info, just send me a private message.

All I can offer is this: you will have very little contact with your bimac if it's shy, but when it does come out to play, make the most of it. Mine has grabbed the tongs I feed it with a couple of times. Both times were amazing. It really had fun, and so did I.

On the other hand, imagine all of the people coming over to my house and me saying "It's in there somewhere, honestly!" Nobody has seen it but my wife and myself.
Yeah, definitely doesn't have the universal appeal of a fish when all you see is a pile of rocks all day. It's worth it to watch him hunt though. Some of my friends don't actually believe I have one in there until they see food disappear once they leave for five minutes.
You've seen your hunt???? I've never seen mine do that. Lately, I haven't seen it at ALL except for 2 legs which reach out and grab the hermit from me in the same spot, every day. I know it's alive and well, but I never see it!

Oh well.
red light

red light

Didn't think I'd post in this forum as I don't have an octo, but still read the posts sometimes. Cool creatures. As far as the red light goes, sells red pc bulbs. A whole 13 watt set-up runs around $20-$25. Just a suggestion. Keep up the interesting posts for those of us that don't have an octo!
I'm thinking of setting up a tank with rocks and pipes and telling people that their is an octopus in it. I think this is better because I will save a lot of money this way.
LOL good idea!

But at least when my piles of rocks start to move about a bit, at least I can see a cool octopus moving about....

Actually, I think that the way I have set up my 2 new octo tanks tends to prove a point. Both of my tanks are very heavily stocked with rocks. Both live rock and a base rock called tuffa along with several 3/4 pipes....

And at any point of the day I could show someone either octopus. They have so many places to hide so they feel secure and choose to sit fairly out in the open, day or night. The only exception is that the vulgaris will sometimes use two snail shells to close the doors onto a pipe.
I certainly think that for my next octo, I'm going to skip the bimac and go for the vulgaris. Since it's larger, it can't hide as much, right? My bimac will hide in holes the size of a pencil eraser, making him invisible almost 100% of the time.
Hi Alligator

Hope you dont mind me saying so but i think that you would be going in the wrong direction if you tried that. The point is that you need to give your pet, whatever it is, a safe, secure, enriched habitat to live in....

What I mean is that if you can provide an environment that is to the animal's liking and that it feels happy in then it will behave more like it would in the wild. In the case of a diurnal species like O. bimaculoides then that means that it will hunt through the day.

That said, there are some octopuses that will settle in quickly to a new tank and be visible. Other times members of the same species may be very shy..... but given time and patience you should be able to gain their trust.

Octopus vulgaris on the other hand is a crepuscular to nocturnal species, meaning that it is most active at twilight and during the night. So in theory you should see it less than bimaculoides.

If you were to keep a vulgaris in a small sparsely decorated tank then you would see it more, but at what cost??? A scared, insecure octopus??? That is not what we would want to do.

May I also remind you that your bimac is still a baby. Behaving as a baby would in the wild by making itself invisible. The more you do stuff to see it... the more it's going to hide. If I were having your problems I would look at the tank and what you have offered it... Perghaps your tank is too bright, my tank is only lit with a small 40watt normal light bulb from above, casting many shadows in which the octopuses sit in. Why not try adding lots more hiding places? Buy a length of 3/4 plastic pipe and cut it into 6" sections and just randomly drop them in... go to a sea food shop and scrounge empty shells, give em a wash and scatter them in.... stuff like that makes life more interesting...

Stick with the bimac, you will learn a lot about ceph care. Once it's bigger and relaxed you will see it much more.....

all the best
Well, as I am the one who started this whole thread. I guess I should give an update. My bimac is getting a little bolder and friendlier lately. I did several things to improve our relationship. I quit "digging" him out, i.e., moving rocks till I found him. There were times I wanted to, just to be sure he was ok, but I left him alone. Then I quit feeding live ghost shrimp and started offering one frozen krill (thawed, obviously) by hand each evening. At first he didn't want to come out and take it, but now he comes out as soon as he smells the krill hit the water, though he still clings to gaps and edges of his rock pile. And now, he doesn't take the food right away and hide, but first grabs my finger(s) and plays a little game of tug-of-war. So I guess things are improving. He's also more than doubled in size since August. I am going to try adding some PVC tubes and elbows to give him something more interesting to play with. But I do need to say that, in my experience, my bimac seems to be very nocturnal. Do they maybe tend towards being nocturnal when they are small?

remember this is comming from somone who never has had an octopus

once your octopus associates you with getting food I bet he will be a lot more willing to come out. he'll think "hey, that's the guy that feeds me." Instead of "oh snap, that's the giant two legged freak trying to kill me."
Thanks Colin, but I'm convinced I have a very shy octo. I only have two 15 watt bulbs for light, and TONS of live rock for it to hide in. I also have PVC in the tank, which he hasn't ever touched.

Can anyone get near their octo to feed it? As soon as I even get within 5" of my octo, he will hide or swim away. I end up dropping the food and waiting for him to come get it. Eventually he will come out if he sees it and eat it.

By the way, it's now been over a week with all the ghost shrimp I dropped into the tank, and he hasn't eaten a single one.

My next step will be to enlist him in a self help group for shy octos! :)

By the way - don't get me wrong, I'm not complaining. I'm just reporting on strange behavior. I really do like the little guy, and I'm sure he has a happy home in my tank. I try not to bother him too much, I don't move rock around and I don't play in the tank any longer than it takes to feed him. He's still alive, so I know he's eating. I just want to counter all those posts where people say their octo is so outgoing that it "begs" at the glass to be fed. Mine is the opposite.
In time, all your bimacs will become more active.
I have a large wild caught bimac and a captive breed baby bimac. The wild caught one was about the same size as the captive breed babies when I got it. It too was shy and seldom seen for the first month or so. I have had this guy now for 6 months and it is very active when hunger is calling.
The captive baby was shy at first but I weened it from feeding off a stick to swimming to my hand and taking food. The captive breed tank has a few pieces of live rock in it with no pores to hide in, There a 4 large turbo snails shells and some 1" pvc pieces in there as well. One trick I use with the litte ones is a take a long probe and use it to push around a small shell. The baby enjoys stalking it and jumping on the shell. When it attacks one shell I play hocky with another shell and it attacks that one. I do this for a few minutes then feed it. It seemes to help my octos adjust to people and like all little kids, they love to play .
slick Chris...
Along the same lines, I never put 2 and 2 together, my Octo can not RESIST when I float a bio ball around in the tank. He HAS GOT to check it out.
Good luck...Jensen. Have patience, and maybe leave his home alone long enough for him to get settled. I know it's hard not to see him. Patience Grasshopper...oh wait, that's in the arachnaphobia board...
Do any of the octopus pages have a list of DIY toys for octopuses? I wonder if they would like those liught up eggs that are sold for bettas.