• 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.

My vulgaris died after two weeks....


Nov 28, 2002
My second attempt at keeping an octopus. First was a baby bimac which died after two days. He was really small and seemed a bit overwhelmed by the overnight shipment.

The vulgaris we bought at a local store. He was about 8 inches from tip to tip, mantle about an inch and a half.

He seemed to be doing fine over the past two weeks. He was eating about 2 ghost shrimp a day. We got home today and found the tank cloudy (whitish). I immediately thought he had inked and did a 33% water change. After the change, I noticed he was just laying there. It wasn't the water change that killed him.

Unfortunately, we threw out the water during the change (not knowing he was dead). As far as I know the water conditions were excellent.

Do octopuses release their ink when they die? We were only gone for 5 hours, could he have lived in the tank if he had inked it? Our cats may have scared him.

Is this sort of success rate normal?

Am I doing something wrong?

Here are my tank specifics:

15g square all glass
Eheim canister filter
10# live rock
4-5" live sand bed
grape/feather/umbrella caulerpa growing everywhere
one powerhead
one airstone to aerate the bottom of the tank
lights: low output flourescent 8 hours a day

We think the octopus had a nice cave built under the live rock. There is one area that we cannot peer into, and when we first got him he started digging it out. He could remain totally out of site if he wanted to.

I have a 37g SPS reef tank, so I think I am no amateur. I hadn't tested the water since we got him (two weeks). Is it possible for that much nitrate/nitrite to accumulate for his size? I would have though that much live rock/sand could handle it with limited water changes.

We're a bit depressed as we don't know what is wrong with the tank.

Thanks for your help.

Hi Josh,

The first week or two are critical in an octopus's life in captivity. Once you get past that it is much easier!

I have several points for consideration...

1) The octopus may have been caught with cyanide. This is quite a common and horrible truth about some wild caught (most octos are) inverts and fish! Two weeks may be a sign of that.

2) A 15g tank is way too small for a vulgaris. You would need something like a 100 gallon + tank for a vulgaris. They can get very big compared to something like a bimac.

3) An octopus produces ~3 times more waste than a fish of similar mass and they are much more sensitive to pollution than a fish. High ammonia levels can kill quickly. If the water was cloudy then this is my best bet on what happened. If an octopus inks, especially in a small 15g tank the water would be a dark greyish colour. I always recommend a good skimmer as standard.

4) Octopuses will die within this timescale if copper is present in the water. Make sure you test your water for copper. It is fatal.

Sorry you have had little success with octos but with a few adjustments there is no reason why you cant get it right next time. Make sure that the tank is bigger (unless you get a pygmy). Cycled for at least three months with mollies or similar, free of copper and with filtration that is overspec for a tank that size. The most important thing is to test the water virtually everyday for the first couple of weeks at least. They are very sensitive to poisoning!!!

thanks for posting your tank parameters, it makes things much easier! :smile:


The water must have been clouded by him dying. It was crytal clear the evening before. I think he died and then released his ink. The water was white/light gray and cloudy.

My water is purified with one of those aquarium pharmaceuticals tap water filter things. It is the same filter I use for my SPS coral tank, and as far as I know there is no copper problem. I will buy a test kit for it and let you know how it turns out.

I guess my next step is a baby bimac as I have credit from a store for the last shipment dying in two days. Maybe I am just incredibly unlucky. I will check the water each day this time. What do you recommend testing for during this period?

Another question. Why do you recommend cycling for 3 months? Is this to eliminate any new-aquarist problems or testing inconsistencies? I usually only cycle my coral tanks for a month since I am using strictly live rock and sand in the tank. A 12g nano reef tank I just started I only cycled for a week and I have already added small coral frags. Are octopuses more sensitive to water conditions than corals? I will get a couple of small fish to see how they do in the tank this time. It has been up for more than 2 months now though, and I have a couple of zoanthids, macroalgaes, and anthelia, all growing even given the low light conditions.

I may break down and buy a remora pro for the tank if I can figure out how to seal it once it is running. Another $250....

I have included a few pictures for you to see my setup. Sorry about the image size.




hi Josh, thanks for posting the pics, thats a nice big bit of LR you have.

The cycling...
Yeah, 3 months is longer than most for cycling a tank. It can be reduced but only by experienced aquarists. Many who visit the forum have never kept an aquarium before and this period is necessary to allow for a very steep learning curve! So I, and others beleive that 3 months is a good length of time for that.
Also, cephs are much more sensitive to water quality than most fish and inverts. This is more so because of their soft skin which has a huge surface area compared to a fish of the same size for example. So they need a mature tank whith no traces of ammonia or nitrite which can sometimes reappear when putting a new animal in too the tank...

Which place are you getting your bimac from? Can they ID them properly? Some places get the species mixed up!

I got the baby bimac from Fish Supply.

I noticed that some of the FAQs stress the importance of RO/DI water. Is it required or just recommended as a way to reduce copper and other heavy elements?

I would say that it is very important to have, unless you know exactly what your tapwater is like... why take a chance though?
They can be a fairly expensive bit of kit for the tank but it is another saftey barrier.
Some LFSs sell containers with RO/DI water for changes, thats always an option...

C :smile:
To expand on what Colin is saying - in this country the EPA standards for tap water are not as high as what is required for a salt-water tank. Some amounts of heavy metals, including copper are allowed.

When I checked into Dallas water standards (and Dallas water is considered to have high standards), I found that I was better off with RO/DI water. This seems to be the case over most of the U.S.

Just a few comments to make about your aquarium.
I don't see a skimmer. Octopus are sensitive to low O2 it is my opinion that a protein skimmer is a must, they reduce filter loading as well as boost oxygen levels.
The filter intake & heater are unprotected, this may cause damage to a healty Octopus.
Your aquarium looks a bit on the bright side. This would not kill but, they prefer dim light.
If it's any reassurance I have kept marines for over 15 years, and work in the aquarium trade. Even I lost my first couple of Octopus, but now have 2 one 7 months old the other about 6 weeks.
Don't get too depressed, Octopus are worth the effort required to keep them

As far as oxygen goes, I did add an airstone to the back of the tank after the bimac died. I think this is sufficient for gas exchange. I have been putting off adding a protein skimmer for the time being due to the cost.

I may remove the powerhead as this was originally to stir the water enough to bring the oxygen to the lower water levels (before the airline was added). This will eliminate any dangers to the ceph. The intake to the powerhead has a filter with very small holes. You are right about the heater though, how do you suggest that I protect it? Keep in mind I have no sump.

I'm not going to buy another one until after the new year, we're going to Costa Rica over the holiday and no one will be able to watch him.

I can't dim the lights anymore, this is a generic low power flourescent that came with the tank (standard on the all-glass of this model).
Well, I didn't have much say in the matter, but my friend bought us a new vulgaris as a holiday gift.

I am pleased to report that I think I may have the friendliest octopus I have ever seen. He has been out most of the day (even with the lights on), dancing around, entertaining us, flashing different colors, etc. He already recognizes me and comes right up to the glass when I put my face close to it.

All the stores are out of ghost/glass shrimp, so we have been feeding him freshwater fiddler crabs. Is this OK? The LFS told us that they like these just as much as the shrimp. He has eaten three of them thus far, and seems to really like them. How do I go about weaning him to frozen shrimp? We put a couple of them in the tank but he hasn't gone near them.

Also, we checked the NO3 levels last night and noticed that it was a bit high (even though we just got him last week). We did an immediate 25% water change. On that note, do I have to be concerned about the stress or shock of a 25% change? We aerated and warmed the water, SG was off one point from the tank. It is now at 1.025. How often should we be changing the water?

Any recommendations for good toys for him to play with? We have been having trouble finding good items that have no metal parts and will sink.

A photo is attached.



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.