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Our octo fiasco, please help!


Nov 28, 2002
Well, where should I begin?

Our octo hadn't been seen in 3 days except a possible sighting when the lights were out in the afternoon on my webcam. My fiance thought he was dead and wanted me to fish him out from under the rock. I suggested running some water tests to see if he was dead or not (I figured I would see it in the water test).

She insisted, so I moved the main rock that he hides under. He was sitting there half buried in the sand, not moving. I poked him a bit and he appeared to move. I grabbed a turkey baster and gradually blew most of the sand off of him. Once he was completely uncovered he let out a huge blast of ink and shot off into the corner of the tank.

I replaced the rock (I couldn't get it the way it used to be, so his old home is ruined) and we immediately did a 25% water change. I also put fresh carbon, silicate, phosphate and nitrate sponge media in my canister.

The water was still a bit dark so we did another 25% water change.

Now the tank is still dark (has hasn't inked again). I am wondering how long I should wait to do my next water change? I don't want him to sit in the ink too long. It isn't cloudy, but it is obviously a bit darker than usual. I am hoping that the carbon will pull most of it out by tomorrow.

A few questions....

Do you think he is sick or something? He used to come out every day to eat and now he hides all day.

How long do you go without seeing your octopus before you start thinking that it may have died?

What should I do next?

I have a perfectly clean reef tank that I can use for a water change if it will be any better than freshly mixed saltwater. For example, I can take water out of the reef to do a change with the octopus tank, and then use freshly made water to fill up the reef. I don't know if this is any better than new water. My reef tank is perfectly clean, no nitrates/nitrites/ammonia.

Any advice at this stage would be VERY appreciated. I'm not sure what to do next. My reef tank experience normally makes me inclined to do nothing and have patience, but it hasn't paid off with the last 2 octos, so I can use some advice.

I'm sorry to hear about your Octopus, it does not sound good.
Even healthy Octopus can be inactive for several hours at a time, but you should see it at least once a day. My well established vulgaris is about about 80% of the time, looking for food. My Octopus seem to have beahviour patterns and do change routine from time to time but always eat well. If they do not eat greedily something is wrong. I would test the water for everything you can and ensure plenty of aeration.

When my current Octo aqaurium was first established I did a 25% water change daily. Provided the water is the same S.G. and temperature this should be OK. Only use reverse osmosis water to make up the S/W.
While carbon is good and is fast acting, personally I prefer Polyfilter's, these remove a wider spectrum of pollutants without any chance of releasing them back. As a safety net I use one in my tank all the time. I assume you have a good protein skimmer, these are a must they are especially good at removing ink.
If possible I would use virgin saltwater rather than that from your reef aquarium. New is always better than used, unless there is a real emergency.
I found with Octopus that are in suspect health you are always better to do something than nothing. All Ceph's can go down hill very quickly if something is wrong. An extra water change or addition of a Polyfilter will never do any harm.
Hope everything turns out OK.

Hi JoshSaul

Well, even though it goes against your instinct and experience, I think you should have patience. You said that your octopus hasn't been out in 3 days.....are you sure? Was someone watching the tank 24 hours a day? :wink:

Almost everyone in this community knows that most octopuses are nocturnal, but many are EXTREMELY nocturnal- they may live out their whole lifespan in captivity without converting to the daylight ways of their food gods. My O. briareus is frustratingly resisting conversion, and it's not unusual to not see him for a few days at a time- he's out at 3:00 am, and I'm not. :smile: If I suspect a problem, then I do get up at odd hours of the night to see if he's around. When my octos finally passed on, they always ended up in the middle of the tank, and not in their dens. I have no idea why, but it's pretty universal. The other giveaway is that usually the ink spills out, and tend to pool on the bottom of the tank.

A better test to see if your octopus is around is to acclimate a fiddler crab to the saltwater. The next morning you will either have a fiddler crab, or fiddler crab pieces. If he doesn't eat for a week, then I'd worry. Try changing food offerings. If your octopus is hiding, good grief, don't harass it.


I'm an opponent of big water changes as the catch all solution. In an emergency they're of course the only answer, and an important part of maintaining a healthy aquarium. But stability in the water is just as important or more important than "perfect water." After upending your octopus's home, poking and harassing him on top of possible sickness, the added stress of constant water changes probably isn't doing your ceph the good you think it is. Marine animals don't just breathe the water they live in, all their biochemical mechanisms depend on it. Here's a great article on the topic. http://is.dal.ca/~ceph/TCP/stable.html

He might be sick, and there's not a lot you can do about it. Gram-negative infections can be fought with chlorampenicol injected into prey items, but that stuff isn't exactly easy to get outside of a lab. You need a prescription and you need to find a pharmacy that can get it! Instead, work towards making as stress free an environment as you can- good places to hide, nitrogen free water, and evacuate all other living things other than harmless corals and macroalgae. Adjust the lighting to nocturnal-friendly hours.

Finally, the end stage of a cephalopod's life is a humorous but sad condition called senescence. Essentially, it's cephalopod senility. Every octopus behaves different in this stage, ranging from eating it's own arms to uncharacteristic social behavior, to uncharacteristic hermit behavior. But one thing is nearly universal: they almost always stop eating when they reach senescence. It's not impossible that your octopus is there. :frown: ...And you have my sympathy if that is in fact the case.

So here's some questions for you:

How large is your octo?
How large is your tank?
What filtration do you have?
How much ink are we talking about? (can you see through the tank?)

Do you have a digital pic of your pet? We might be able to ID him positively and then we might get some bahavioral cues from that.

Other than that, good luck, and may the Force be with you.

Well, in answer to your question, I do not have a protein skimmer. I made up for the oxygen exchange by adding an airstone to the back of the tank.

Also, we purify water with an aquarium pharmaceutical tap water purifier. I use the same water for my reef tank. I live in Manhattan which actually has the cleanest water in the country (we have higher water standards then any other city).

There are three types of sponge media in my canister in addition to the rock type stuff. They are a little old, but I do clean them each time we change the other media.

We put a fiddler in last night to see if he would eat it. Before, we had been waiting to see him come out before feeding, as we were hoping to condition him to associate us with food. I'm going to make sure that there is at least one live fiddler in there at all times so he always has something to eat.

This is pretty frustrating. This is my third octo. The other two both died in under two weeks. We were getting attached to this one, as he was very social and interacted with us for the first two weeks. Also, it really screws with my sense of confidence as my all SPS reef tank is pristine and never has any problems. It is MUCH more complex as far as equipment and water conditions.

I wish I knew what the problem is with my tank.

Thanks for the info.

In answer to your questions:

The octo is about 10-12" from tip to tip. Mantle is the size of a large date.

I believe he is a vulgaris from Fiji if that helps at all.

My tank is a 15g square, eheim canister filter, one spray bar, one powerhead, one airstone. 15# live rock, 20# all live sand, a few macroalgaes for color.

Lighting is a 9w flourescent which is on about 8 hours a day.

Nitrates: 0
Nitrites: 10-20ppm max before a water change
Ammonia: 0
PH: 8-8.3
SG: 1.024-1.025
Temp: 78-80

As per my previous post, water is made up with a tap water purifier. I do not have an RO/DI unit. It is the same water that is in my two other reef tanks. I have never had a major problem (other than self inflicted) with my water in the 3 years that I have had my reef tank.

The rock was arranged fairly well, and he had dug out a den underneath the main piece. We added a piece of PVC tubing and a small floating cat toy last week for amusement.

Here are some photos to give you some idea of the tank setup:



And here is one with him eyeing a fiddler:

Hi Joshsaul-

DUH! I knew I'd seen pics of your tank and octopus in another thread. My apologies. Everything looks pretty good, but I'd cool that water off a bit. High temperatures don't do octopuses any good, and evidence seems to indicate it ages them faster. If coral is living in your tapwater-made Saltwater, then it's fair to assume an octopus would be OK too.

One thing about octopuses- if you make their tank "the food tank" one of two things typically happen: A) they gorge themselves, killing all the prey items and snacking only on a couple bits of them, leaving the bidies to rot (UGH!) B) They start thinking of the prey items as roommates instead of meals. I had an octopus that once relished strawberry crabs, but later wouldn't touch them. Make mussels for dinner tonight and give your octopus one and see what he does with it.

I'd call it a fair bet your octopus is O aculeatus or some relative, a common species from Bali/Indonesia/micronesia/over there somewhere...:smile:

These octopuses are sold as "bali octopuses" by www.ffexpress.com and are becoming common in the pet trade because of their hardiness and easy-to findness.

I have kept four of them, and three died mysteriously after not long in captivity- less than a month. Being from that region, it's perfectly possible that they're being caught with cyanide and that's the culprit- not something you're doing wrong. One exhibited the same behavior you're reporting: Social and playful one day, a fasting hermit the next. Death followed a week later.

He may come through it, he may not. Again, I think the stress-free element of the tank is his best chance. BTW, you really should get a bigger tank for your cephs. Something with lots and lots of rock to explore and make den sites in.

Either way, cephalopods are tough to keep, and even my friends at the NRCC have had head-scratchingly confusing die-offs from time to time. Don't lose hope- for all the high maintenance, I still think cephalopods are by FAR the coolest thing you can keep in a box of water.

For your next go around, get yourself a bimac. can't go wrong with a bimac IMHO. :biggrin2: Good luck!

Cheers, Jimbo
I wish I had the room for a larger tank, unfortunately we live in NYC!

The first octo was a baby bimac from Fish Supply that died in 2 days. I think that was due to the shock of the trip. I still have a credit from them for a replacement.

Should I take the mussle out of its shell?

We are going away for a week and will have someone drop 2 fiddlers in there every 3 days or so. I hope this doesn't get him burnt out on them, glass shrimp are a bit hard to find here right now.

He he he he, being one who just moved from a three level single family home into a one bedroom apartment, I understand completely. Of my 300+ gallon saltwater lab shrimp and oct hatchery, all I have now is the one tank.

As for the mussel, nope don't shell it. In fact, acclimate it to your tank as you would something you bought at your LFS- being very gentle since your LFS generally doesn't pack their critters in ice.

I've had a couple octos really take to mussels, but they pull the shells open as opposed to drilling them. In the wild, many octopuses eat shellfish (bivalves and gastropods) and use their radula to drill a nearly perfect hole in the shell exactly where the adductor muscle attaches. They drill it through and the hapless mullosk pops right out.

On the last expedition I was on, we collected octopus middens and most of them were drilled shells. I'll be darned if I could figure out where the octopus was finding the shells though. I couldn't find many mollusks

Oh well. Good luck with it!

OK, it looks like he ate the fiddler from last night. How should I proceed with feeding him? We were trying to save food until he actually came out a bit, but if he is sick or stressed I would just rather have him eating something.

Should I put a new crab in once he eats the old one?
joshsaul said:
OK, it looks like he ate the fiddler from last night. How should I proceed with feeding him? We were trying to save food until he actually came out a bit, but if he is sick or stressed I would just rather have him eating something.

Should I put a new crab in once he eats the old one?
Hi josh

I normally always wait until the octo is out and hunting before i put food in. I found this to be the easiest way to be associated with food and therefore a good thing:smile:

Maybe at first keep putting an item of food in every day or two, until it settles a bit better

good luck
Well, I am glad to report that he seems to be doing a lot better. We haven't really seen him too much, but no more inking and he is definately eating the fiddlers.

As far as variety, we did give him a crayfish at one point. I think he liked it but that was around the same time that he stopped coming out.

We are going away on vacation tomorrow (Costa Rica!) and we bought 20 ghost shrimp and one fiddler for him to eat over the next week. We have someone who is watching our cats that will be doing the feeding.

Thanks for everyone's help! I hope he starts coming out a bit more in the new year.


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