Horseshoe crab?

[Oceanic Art]

@DWhatley @sirreal
The issue is with N02, its reading 0.2 on the chart, its a Red Sea test kit, also had the fish store test it and shows N02. The other day I hadn't seen Taco in a day so I moved around his rock to see if he's ok. He'd eaten a fair bit the days before so I wasn't super surprised he was resting for a bit.
Once I moved the rock, he swam around the tank for a bit and went back under. He's been there for two days now, the webcam shows no movement, he's barricaded himself in with shells and rocks. I offer food at the entrance to his den but hasn't taken any.
Should I take emergency measures to get rid of the N02 at this point or should I keep up with the water changes. The changes show no real change in N02 and Tack seems to have become very reclusive, he was swimming around during the day last week and kept his eyes out almost all day watching us. Please advise.

 

[DWhatley]

Tough call. There are several possibilities to explain the behavior you are describing.
(1) Stress from the nitrite
(2) Tack is a female and has started to brood (often females about to brood are easy to catch as they load up on food before sequestering themselves). The robust eating followed by not eating can suggest this.
(3) Anecdotally, a newly captured octopus will take about 1 month to fully acclimate to tank life. There is often a distinct behavior change (often from outgoing to reclusive) around this time. The next "phase" can be anything from very shy to moderately active and seems to depend upon the individual.

Personally, unless you are observing a breathing issue, I would not add a chemical neutralizer but you might increase your water change amount slightly. I also recommend NOT moving the rocks around to find her/him as this is a stressor. They need to feel that they can hide. I know this is very hard to do and I have been guilty of moving a rock or two after odd behaviors. Sometimes it is possible to provide a rock that can easily be moved for a peek but then replaced to give the desired seclusion.

 

[sirreal]

So when this happened with Casper I did take drastic measures which did not help. She started brooding and then passed about 2 weeks later. I am starting to wonder if the poor water quality pushes them to brood early?? One of there main life goals is to reproduce so if they start to decline in heath they might brood before passing. Of course I am no Biologist and have not studied this anymore then reading here and online. It would make sense to me.
As far as what to do for I agree with D. Make sure there is no left over food as that might be the cause of your N02. What do you have for flow in your tank? If you don't have a lot of flow increase it and move flow pumps lower in the tank to move the water from the lower part of the tank. Stagnant water can be an issue as to why your system is not completing the Bio. What are the rest of your parameters?

 

[Oceanic Art]

Ok I'm going to do a lot of tests and increase flow rate and such tomorrow. I saw a tentacle yesterday morning come out of the rock on my webcam, nothing all day today and no movement.
I fear maybe it's a girl and maybe she's broody, but after the story about yours I'm afraid.
The tank had been cycling for almost two months before I put Taco in, so I assumed it would be ok.
I'm not going to take emergency measures after all the considerations and it maybe not doing anything except possibly costing the gills.
Only one time I saw taco breathing heavy was when he/she was coming out for the first time in front of all of us. Thought it was nerves maybe.
I hd assumed Taco was a male because of his one short tentacle, was told that this was a male because of that. I'll try and upload a few videos from last week.
Should I check the rock now? Leave it alone? Just keep on with water changes? @DWhatley @sirreal

 

[Oceanic Art]

IMG_6991

• Oceanic Art
• May 9, 2017

Taco the octo

 

[Oceanic Art]

Also I removed the fish from the tank after this video upon your reconditions

 

[DWhatley]

I was going to ask about the clown. I think I would leave well enough alone and just watch for the next couple of weeks. Do try offering food on a stick near the den daily. A short arm is the sign of predation, a curled up arm (third on the right - clockwise as you orient your eyes with the octos) is the implication that the animal is male. Here are a few photographs of the curled up hectocotylus of several species. I can't tell one way or the other from the video as they will curl all their arms at times. The specialized arm usually remains tightly curled even when the other arms are hunting.

 

[Oceanic Art]

Ok ya the shirt arm was on the left side not the right so I think Taco may be a female.
I have a nest cam which records the tank 24/7 and haven't seen any sign of anything for at least three days. No substrate disturbance, no food eaten, nothing. I'm concerned. Any other steps I should take at this point?

 

[DWhatley]

Test your water daily and watch for an ammonia or nitrite spike that might suggest she has died. If you can arrange a peaking doorway (removable rock that does not fully disrupt the den), you may want to try setting this up. Some of mine allowed an opening large enough to view within, others have insisted on closing the den up completely. Ensuring a gentle flow of water to Taco and the eggs may help.

Brood times vary highly with species and water temperatures. For the aquarium sized animals, large egg species tend to more eggs and a longer brood time than small egg species but the colder the temperature, the longer the brood cycle. Even though a GPO lays small eggs, they have the longest hatching times for aquarium kept octopuses (roughly half a year -- the longest brood time was recently estimated at 3 years for an arctic species observed with an ROV, egg size not mentioned/known). Start watching for hatchlings after 3 weeks but it may be considerably longer. Guessing from the size of the octopus, there is a fairly good chance the eggs are fertile. Sadly, there is almost no chance any of the hatchlings will survive. The full hatching may take a full week but three days is the most commonly observed with the majority hatching on day 2.

Typically the female will die just after hatching would naturally occur (even for infertile eggs). We have seen females die both earlier and even a full month later . Typically she will exit the den at the end of her life and may wander about restlessly (in the wild, she would be an easy target for predators but in a tank may live a bit longer). I have noted that the mantle is often bloated and lacks control during this end of life senescence. You can offer small food but it is unlikely she will eat.

 

[Oceanic Art]

Ok so the nitrite have gone down considerably, either at zero, or at the very most .05 ppm. The nitrate is between 5 and 10, ammonia is reading zero. So I guess I'm happy with the water readings, hopefully something starts going right soon for Taco.