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Officially lost 2 octos :( What's wrong?


Pygmy Octopus
Feb 25, 2003
My tanks (octo and bait) were set up last July. I always wanted to have an octopus and set up the tanks with that specifically in mind. After everything cycled I got my first octo in November. It presumably died at the end of December. I got a second at the beginning of March. It now has been missing since the end of April. I'm so sad. I now feel I should get something else (my manfriend wants a clownfish), but I'd rather find out why this is happening. Any advice anyone has is welcome. Here are my readings for both tanks this week. As I am a begginer with marine tanks I am still finding what levels of what I need to add to keep things at the place I want them. I'd love to say my levels are always steady with everyting, but they aren't. Calcium and I aren't friends. It goes up, I stop adding, it goes down, I can't keep it up. And lastly we don't really keep the heat or air on in our house and I'm wondering if a flux in temperature would be the issue. Thanks for any comments.

25 gal
76 F Temp (will vary up or down 3-4 degrees based on weather)
8.3 pH
0.5 Ammonia
0.1 Nitrite
5 Nitrate
350 Calcium
0 Copper
7 ppm Oxygen
1.024 Salinity
8 Alkalinity

50 gal
72 F Temp (will vary up or down 3-4 degrees based on weather)
8.3 pH
0.25 Ammonia
0 Nitrite
5 Nitrate
350 Calcium
0 Copper
8 ppm Oxygen
1.024 Salinity
9 Alkalinity

Thanks again.
I'd really like to have some more information before giving you an answer. What's in your tank - do you have live rock? Any thing else living with your octos?

What kind of filtration do you have? If you have a pic, maybe you could post it.

Also, what species of octopus - do you know? How big were they, and what did you feed them?

The tanks both have live rock and sand. For filtration I have in each tank a remora pro skimmer and a penguin bio-wheel (330 and 170). Nothing else living with the octo. There is a feather duster and a peppermint shimp in the bait tank.

The octos were both fed lots of little clams. Both had some small snails and hermits in with them too. The first liked snails the best, the second liked hermit crabs. Both ate really well the first week and beyond. Both were fairly small when I got them...I'd say a mantle of half an inch. First was from Fishsupply. Second from Octopets.

Thanks for your help Nancy.
Sounds like flux in water quality is the issue.

You shouldn't be getting ammonia readings like that with a well cycled tank. Did you use any chemicals or carbon/resisn or a protein skimmer while cycling the tank? What biological load (ammonia producers) did you use to cycle the tank? Or did you use chemicals? Did you leave the fish (if used) in when you added the octopus? How big was the octopus compared to any fish (if you used fish) you used to cycle the tank? Did you break down the tank and start over at any point? What happens to your Ph when you add the Calcium (btw, pH is on a log scale so a change from 7 to 8 is a 10 fold change). I've never bothered adding or testing for Calcium in octopus tanks and can't think of a reason why they would need coral reef levels. I can think of a reason that wild swings in pH or ammonia would kill them. . .

I doubt temperature changes in your house are a factor.

Do they eat ALL the clams? Did any die and rot?

The tank cycled July 2004 - August 2004 with only live rock and a protein skimmer. No fish. I can't guarantee my ammonia, nitrite and nitrate are really at those levels, as I was eyeballing the colors late at night during the last test. The ammonia could be due to the death of the octo or a wrong interpretation of color. I've never seen a body so I'm asuuming it is disentegrating. Looking back at my testing from August until now Ammonia ranged from 0 - .25 (the next lowest reading on my kit and if it's hard to tell, I write down the high number), Nitrite was normally 0 and nitriate was 0, 5 or 10.

My notes say the limit for these readings is: Ammonia .2 ppm, Nitrite .2 ppm, Nitrate 100 ppm.

I do a 10% waterchange faithfully every weekend. All of the other invertebrates seem unphased.

To be truthful, I don't think it's the ammonia. I've got a protein skimmer, bio-wheel and the live rock all working on it. I never thought about the clams though. The first time I put the clams in a dish. The last two times I got clams, I let them bury themselves in the sand. I appreciate your time in relplying.
This may be a difficult one to figure out. If you're having trouble with your water tests, maybe buy a second ammonia test from another manufacturer and make sure you're getting accurate readings. It's important to know whether you have ammonia or not. Examine the colors under a good light. The only tests you really need (in addition to sg and pH readings) are nitrite, nitrate and ammonia. Nitrite and ammonia should be zero, but octos can tolerate a bit of nitrate.

James may be onto something - the water quality may have been compromised by dying clams or some other reason. Both your little bimacs managed to live almost two months, which is something. I'm also wondering about the quality and quantity of food they ate. Did they both continue to eat crabs and snails and other live food, or mainly clams? What did you keep in the "bait" tank - any other food?

Good idea on the second test equipment. I will assume then for now the ammonia has been too high. I guess I should clean out my sand and get rid of any empty or dead clams.

The octos were both pretty small and the majority of their food were the clams. They tried to go after bigger prey. Sometimes they could handle the snail or crab (attack and eat), sometimes an invert would poke it's head out after an attack and continue on it's way.

The bait tank normally had snails, red hermits, blue hermits and the peppermint shrimp. The peppermint shrimp has taken to eating a hermit every once and awhile. Before that he decimated my margarita snails. I think he took down 20 in a pretty short time.

I'll clean up all of the shells and stuff in the sand. Wait a few months and see how my ammonia is reading.

I appreciate everyone's input.
With regards to cleaning, I'd advise that you clean more and be sure to keep up water changes and watch the food *when you actually have an octopus in the tank* and to not overdo it on the cleaning when you don't (you don't want to clean out the good bacteria that you may established when/if things went bad). If you did have an ammonia spike, it has been processed by now and your sand is full of even good more bacteria.

If you decide to try another octopus, I'd make sure all levels, especially ammonia are low (zero for ammonia) and would do a bigger water change a few days before you add an octopus to the tank.

Using a second test kit is a good idea. So is keeping track of the food you offer. Some octopuses will kill everything in sight but only eat a fraction of it. . . frustrating!
The clams may be a cold water species put in a warm tank. . .

Did you see any changes in the other inverts around when the octopus died? Do you have any corals or non pest anemonies on the live rock?

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