Axie frantically swimming, trying to escape tank

[sliemm]

I have a 120L tank with 2 axies. Today I did a water change of about 30% and cleaned the filter of grime (I was gentle with the media, sponges etc), as well as put new charcoal in the filter.

As the tank was getting a little green I put some tank salts in there to clear the water. Some of the new water was tap water - I realise it has a chlorine content, so I gave it some time to dissipate then put the axies back.

One axie (Eric) is fine, but Ernie went crazy. He started zooming round the tank at an angle, poking his whole head and shoulders out and looking like he wanted to desperately escape the tank. I put him back in a tub for a while, thinking it could be the chlorine. I also did some chemical testing - ammonia levels and nitrite levels are zero, so it's not a chemical imbalance.

I find it hard to believe it's a bad environment in there if Eric is doing fine. I've tried reintroducing Ernie a few times now over the space of a day/evening, but every time it's the same result - he goes crazy trying to escape. When I put him in the tub he just floats there, not looking too happy. Infact the fact he's floating on the surface of the water of the tub is also worrying; he's not sitting on the bottom of the tub.

Any ideas? Thanks in advance.

 

[sliemm]

Also, now he is in the tub he is floating and listing. He doesn't look happy.

 

[LSuzuki]

Axolotls react differently to substances, so it really could be the changes you made, even if Eric is fine. Or Ernie could be sick and it is just a coincidence that you changed things in the tank, but that is unlikely.

So, a) you changed water, b) cleaned the filter, c) changed carbon, and d) added tank salt to kill green stuff. The first two of those should not have caused this problem if done correctly. Changing the carbon should only have caused a problem if the replacement carbon was contaminated with something. (Did you rinse it before putting it in the tank?) My guess, however, is that the tank salts are directly or indirectly the cause of the problem.

By tank salts, do you mean what we call aquarium salt? NaCl, without additives? Or is this something different designed to kill green stuff? How much did you put in? Regardless, if it killed algae or whatever, whatever was in the stuff that it killed is now released into the water.

So, my guess is that Ernie is more sensitive to something than Eric, and that something is the tanks salts, something the tank salts killed, or something contaminating the carbon.

I recommend changing as much of the water as you can. With a water change this big, make sure it is dechlorinated before putting it in the tank, or put the dechlorinator in the tank directly before putting the water in.

The other thing that concerns me is the green stuff, since sometimes that indicates too many nitrates. Do you test for nitrates? How often have you been doing your 30% water changes? That probably isn't the cause of the current issue, but it could cause future issues.

Good luck with Ernie.