Can you be more specific? Pygmy octopus can go with several different species that have pretty temperature requirements. Do you know where it came from? If not, could you provide a picture for us to ID? Also, it would be nice to have units with your measurements, especially oxygen. There are a bunch of different units for measured oxygen, so it is hard to know what your numbers mean.
Well I know this pygmy was shipped from South Africa. Since my camera is being dumb, I'll just describe what he looks like. He does have webbing between his tentacles, is really tiny, when he is not trying to blend in he looks almost colorless, but has what kinda looks like these little fluorescent dots all over him. Those above water levels I got from a report of the average water quality that species lives in in the wild, so I though that would be good to use as a rule of thumb since I am totally new at this. He seemed to do fine when I introduced him to the tank yesterday. Maybe if you have a pygmy tell me what rules you use for water quality? Also this does not have much to do with anything but when I first got him I noticed he was missing two tentacles and another seemed to be missing half! Will he be okay? Can he grow them back? He seemed to be plenty active anyways.
Interesting description and location. This will be a new one for us so I hope you journal the experience and get your phone's camera to smarten up . For the US southern East Coast and Indonesian animals 68F is quite cold but no so for most other places in the world. Native water temperature will be the best guess but you need to determine both the range (summer - winter) and the general depth (ie does it live in the shallows vs in deeper water). I would recommend choosing an average of what you can find rather than a seasonal temp, moving toward the warmer end if (as is likely) this is a shallow water species. Do note that colder water animals tend to live longer than the warmer water species.
Nitrate is not much of a concern and they will likely rise due to the waste. Ammonia and nitrite, however, need to be controlled so that they are never detectable. Your tank needs to be well cycled (think fish about the same size). A newly cycled tank (under 3 months) will not typically handle the bio-load (a dwarf species is less polluting than the larger animals but will still add more waste than fish).
All known octopuses can regrow their arms. Very few come to us with all eight arms in tact (I have found this to be true even of very, very young animals). The main concern with any injury will be infection and we don't usually see arms displaying this problem. Watch for a tiny "string" developing at the truncated site. Slowly you will see tiny suckers develop and then the new growth thicken.
Thank you for the help! I have the water and 73F right now and the salinity is at 36. He seems to be doing fine, he was quite active earlier and was playing with some shells and crawling on my fingers. Its good to know the tentacles will grow back!
Aaaaaaand he is dying. I don't get it. I tested the water not even an hour ago and all seemed fine, the temp and salinity are stable. There is no bright light in there and plenty of hiding places. Twenty minutes ago he was wondering around exploring. I fed him mysis shrimp yesterday. I just walked in and he is on the ground (sand) not moving, except for the occasional tentacle twist that just makes it look like it is in pain, and he keeps putting brown coloring into his face and letting it go away again. I am so frustrated. I took a responsibility for a life and three days later it is dying and I am not sure why or what I can do.
It's very sad that your little octopus is not doing well. Did you just do a water change or make any other changes to the tank? What about pH? Are you testing for that? Some salt mixes produce salt water with a lower pH than octopuses prefer - it should be around 8.3. A little lower or higher would not kill your octopus. The arrival of your octopus happened so fast that you didn't have time to cycle the tank or fully learn how to care for an octopus.
If your octopus survives, you should plan to do many water changes to keep the water quality good. Some years ago we had octo owners in a similar situation: a small octopus in an uncycled 30 gallon tank, and they managed with frequent partial water changes.
Shipping is very hard on octopuses and the first two weeks seem to be the critical time on how well they will acclimate. For future considerations keep in mind that they must be shipped overnight and in a large volume of water. Often shippers try to reduce the costs to the customer by not supplying enough water but the result is often fatal. You also need to SLOWLY fully match the shipping water with your aquarium water so that temperature, salt and PH are the same. For an overnight shipment from FL to GA it usually takes me 3 hours to do the match. If the animal inks the bag, very few survive. This is the only case where fast acclimation and a lot of finger crossing are important. Lighting is not a concern but it does need a completely dark shelter to hide. If you don't have a place for it to completely hide, this can stress the animal enough to have it die. Has the tank ever held fish and if so have you ever used a copper based medication to control ich? ANY copper in the system will kill an octopus and most invertebrates. The general recommendation is to avoid used glass tanks if it ever held fish because copper medication is almost always used and may be absorbed by the silicone seals, leaching out over time.
At this point, there is nothing you can do but hope it recovers -- the chances are not good. DO check your salt and PH but, sadly, I am afraid it will not make it. Often we don't know why they don't acclimate ( 2 weeks is my survival acclimation estimate but full adaptation to tank life takes about 1 month). Sometimes the animals are full adults with little time left and shipping shortens that time. Sometimes they are post brood females and are destined to die very shortly. The older, senescent animals are easier to catch as they often are out wandering aimlessly. Did it eat anything during the three days you have had it? Senescent animals stop eating but often over stressed animals will either over eat or not eat at all.
Thank you! He died in the end... it was really sad. But I decided to go ahead and put some easier fish in the tank and see how that goes, and slowly work my way back up to an octopus someday after I have more confidence in my skills running an aquarium. Someday I would like to work in an aquarium keeping an octopus!
Sorry that your little octopus died.
It's a good idea to keep a reef tank and get some experience with a marine environment, learning all about water, testing, acclimation, etc.
Some day you can try again, with a much better chance of successfully keeping an octopus.
One of the things you will learn, is that a larger aquarium is much more stable. You only had a 16 gallon aquarium, when something goes wrong, it really goes wrong in such a small system. I would wait before putting anything else into such a small system right now.
I'm not sure where you are located in the U.S. - but could you volunteer at a nearby aquarium? Often there are also reef clubs in many cities where you can meet people with lots of experience working with salt water aquariums.