First ever post, just got octopus.

[bizandheath]

Hi, my name is Heath and I just got my girlfriend (her name is Biz) an octopus for her birthday. There are a couple of knowledgable shop owners in my town and they were able to set me up with a suitable tank (sealable) that was already cycled and they gave me all of the live rock and sand and the water that was already in it. I had everything set up for ten days or so and tested the water several times before ordering the animal. I put some snails and a ring-tailed shrimp in the aquarium about seven days before the octopus arrived just in case it was hungry right away. We were able to get a bimac and she arrived on Tuesday (10/02/07). We had several name ideas, but we finally settled on "Detective Hachi" (Hachi is the Japanese word for eight).

These were the levels when we put the octopus in to the tank.

pH 8.4
Ammonia 0
Nitrate 5 mg/L
Nitrite 0 mg/L
SG (salinity) 1.021
Temp. 76.1 F

From all of the material I've read, this should be a perfectly comfortable environment for Detective Hachi. It didn't eat anything for four days, so I finally went and bought eight hermit crabs and it ate two of them right away, so it seems like Hachi is now adjusting well. The first two days it mostly hid, but on the third night, it was fairly active and explored the tank for several hours.

Here are some of my questions / concerns that maybe the more experienced octo owners out there may be able to help me with:

She (at least I think it's a she) is a bimac. How can I be sure about identifying the sex?

When I got her, each tentacle was about 10 inches long. Any guesses on how old she might be?

My ammonia went up slightly (from 0 to 0.25) but nothing has died in the tank and I haven't added anything foreign besides the octopus and hermit crabs. What might be the cause? What might be the solution?

According to her size (10 inches) how much / how often should she eat? Or is it OK to just leave the aquarium stocked with crabs and let her eat at will?

Well, I look forward to hearing from some of you soon.

 

[monty]

Heath, Biz, and Hachi!

It sounds like you've got things pretty well in hand. I'll toss out a couple of thoughts, but I just read a lot of this, so the experienced ceph-keepers will probably have more specifics to say. Just in case you haven't found them yet, the articles tab at the top has a lot of ceph care articles that are pretty helpful as a reference.

One thing that will probably help is knowing how big the tank is, if it has a sump, and what kind of filtration it has. A bimac with 10" arms is pretty big, so I could imagine that, particularly in a small tank, the biofiltration wasn't quite up to the load of the ammonia the octo produces naturally. I'll defer to the experts on what that would mean, but you should definitely keep monitoring it, possibly do a partial water change, and maybe consider adding more filtration. But it also may be minor enough that it'll stabilize on its own...

I can say that an octo won't overeat, although there is some belief that feeding it as much as it wants will shorten its life a bit. It also might make it more likely to not "clean its plate" and leave partially eaten crab parts for you to clean up.

I think the only way to sex a bimac is to look for the modified arm on the male, which is pretty subtle and may not be present until sexual maturity.

I hope this helped a bit, but I'm out of my league on the best response to the ammonia, so I hope others will chime in soon...

 

[bizandheath]

Thanks for the feeding tips.

The tank is 39 gallons, it has a hood filter: polyfilter, filter floss, active carbon, and bio-filtration rings.

Also, the ammonia test kit I have is a SALIFERT test and is pretty sensitive. I tested the "pure" saltwater that I got from the aquarium supply place and got pretty much the same reading, maybe I'm just being overly cautious.

The other thing is that monty says 10 inches is "big" for a bimac, but does "big" also mean "old"?

 

[DWhatley]

Biz and Heath,
Great to have a new keeper!

Octopuses grow to different sizes within each species. Even sibblings vary greatly. When you say the arms (squid have arms and tenacles but octos only have arms) are about 10" are you referring to the length of a single arm from the mantle to the tip or the span across two arms with the mantle (body) in the center? Also, guestimate how large the body is by comparison to a fruit or other ball shaped object. Pictures are also helpful (and just plain desirable).

Please monitor you ammonia very closely. Since your tank was reassembled to create the environment, you may be going through a mini-cycle. Be sure to do a water change at the sign of any ammonia. I would recommend a 10 percent change weekly with the bioload additon and the instability you have seen.

You should also bring your salt content up a bit (over a period of several days) and maintain it closer to 1.026 as full ocean salinity is needed for an octopus. One simple way to do this is to top off the tank with saltwater rather than freshwater but be sure to check the levels before you add the new water (not directly after you top off).

 

[cuttlegirl]

Biz, Heath and Hachi,

I would add a protein skimmer to your set up to help remove the waste from the water. Octopus produce a lot of waste (since they eat a lot...).

Also, given the size of your octopus, the tank seems a little small. You will have to monitor the water quality and may have to do partial water changes to maintain the water quality.

 

[Animal Mother]

Welcome to TONMO! Looks like everyone's got you taken care of. The third right arm will be the hectocotylus if it's a male, if it looks the same as the other arms, it's female.

And give us pictures! Please?!

 

[bizandheath]

Thank you everyone for the great tips.

Still trying to figure out an approximate age in mos. according to Hachi's size. Sorry, no pics yet, I don't have a digital camera or a scanner or anything. Perhaps my earlier descriptions may have been to vague, so hopefully this clears things up. Each arm, mantle to tip, is about 10 inches. Her mantle is approximately 3.5 inches long and about 2 inches wide. According to the vendor, this octopus was considered "medium" in size.

As for my water quality concerns:
I did a 10% water change and added an 1/8 cup "instant Ocean" salt a little at a time into the polyfilter to try and get the salinity up. Also, the heater I have supposedly has an internal thermostat, but the temperature fluctuates by as muchs as 6 or 7 degrees F per day, is this normal? What is the highest / lowest temperature the octo will withstand? Also, some material I've read says they like it around 75 degrees, and others say around 79 or 80 degrees is optimum.

I think I'm going to get a bit more live rock and add in some more bio-filtration rings to see if that helps with the ammonia. If that combined with frequent water changes doesn't help, it looks like I'm going to have to get the protien skimmer.

I'm about to retest in about another hour or so and will post the new numbers.

 

[Animal Mother]

Bimacs are cold water species. 75 is about as high as you want to go, lower if possible.

You don't want to put the salt mix into the tank itself, you should mix it into your topoff water first and make sure it's dissolved first.

 

[Nancy]

Hi and welcome to TONMO.com!

I've added your octopus to the List of Our Octopuses!

Sometimes O. bimaculatus and O. bimaculoides are confused. Most of what we find available for sale is O. bimaculoides and that's what we refer to as a "bimac"

Have a look at this article about O. bimaculoides
Cephalopod Care

Can you see your octopuses' ring (false eye spot). If it's the same as this, you most likely have an O. bimaculoides.

Nancy

 

[gjbarord]

Leaving prey items in the tank may sound like a good idea, but if you are already experiencing water quality problems then you should probably remove the extra crabs and place them in the tank only during feeding time. After all, crabs produce nitrogenous waste as well. Just be sure that you are not doing too many water changes, or very large water changes, as this may only lengthen the time it will take for your tank to cycle through this. This type of spike is quite normal after the addition of an octopus.

"Big" may not always mean old, but "big" almost always means that the animal has progressed to its latter months. An octopuses' life span is dependent on a number of things such as temperature and diet. Octopus in warmer water will tend to feed more often and grow quicker. Octopus in colder water will tend to feed less and grow less. So, you could have two O. bimaculoides side by side in different tanks, with different temperatures, that have a vast difference in life span. Hope that makes sense. My point is, unless you know the history of the animal you cannot be very sure about its actual age since it does depend on so many environmental factors.

Greg

 

[AD2U]

Hi, my name is Heath and I just got my girlfriend (her name is Biz) an octopus for her birthday. There are a couple of knowledgable shop owners in my town and they were able to set me up with a suitable tank (sealable) that was already cycled and they gave me all of the live rock and sand and the water that was already in it. I had everything set up for ten days or so and tested the water several times before ordering the animal. I put some snails and a ring-tailed shrimp in the aquarium about seven days before the octopus arrived just in case it was hungry right away. We were able to get a bimac and she arrived on Tuesday (10/02/07). We had several name ideas, but we finally settled on "Detective Hachi" (Hachi is the Japanese word for eight).

These were the levels when we put the octopus in to the tank.

pH 8.4
Ammonia 0
Nitrate 5 mg/L
Nitrite 0 mg/L
SG (salinity) 1.021
Temp. 76.1 F

From all of the material I've read, this should be a perfectly comfortable environment for Detective Hachi. It didn't eat anything for four days, so I finally went and bought eight hermit crabs and it ate two of them right away, so it seems like Hachi is now adjusting well. The first two days it mostly hid, but on the third night, it was fairly active and explored the tank for several hours.

Here are some of my questions / concerns that maybe the more experienced octo owners out there may be able to help me with:

She (at least I think it's a she) is a bimac. How can I be sure about identifying the sex?

When I got her, each tentacle was about 10 inches long. Any guesses on how old she might be?

My ammonia went up slightly (from 0 to 0.25) but nothing has died in the tank and I haven't added anything foreign besides the octopus and hermit crabs. What might be the cause? What might be the solution?

According to her size (10 inches) how much / how often should she eat? Or is it OK to just leave the aquarium stocked with crabs and let her eat at will?

Well, I look forward to hearing from some of you soon.

Try to keep the salinity at 1.024-1.026 like a reef tank.