Illness/Sickness: Lost frills overnight????

Hi! I'm new to the forum & new to axolotl raising, and am a little desperate for help... I'll be as detailed as possible.

I have a 6 month old and a 3 month old axolotl, who are kept in separate tanks. The younger one was big enough to move to a glass tank, so due to space, I moved my 6 month old (around 5.5 inches) to a 10 gallon (previously 20) and my 2 month old (about 2 inch) to a 5 gallon. They both used the exact same water, same sand substrate from the older one's tank, and even some of the same decorations and stuff. For this reason, I don't understand if its a water thing- Because the older one, overnight, lost her gill filament and the young one is okay.

The older axolotl was also swimming to the top a lot to get air, and seemed very lethargic. Would only eat if I handed her food, instead of in her bowl.

The ONLY thing aside from size that was different about her tank was that I usually have a filter set up to oxygenate/clean the water, but I had to buy a new filter, so I didn't put it back in until morning, and since I put it back she seems...less lethargic? It has been one more day since the tank change and she seems even less lethargic- swimming around and stuff instead of sitting in one place all day, but I'm still worried...

-can she breathe okay?? Should i lower the water level so she can swim up to get air easier??
-is there anything I can do to help her grow her gills back? Will they come back?? She looks so sad

here are some photos:


here is their tank

Here is my older axxie the night I changed her tank

The next morning (morning after)

This morning

And here's my younger axxie, lookin' fine this morning!

Hi there and welcome to the forum. :happy:
I've only been keeping axolotls for around 3 months, but I'd say that it's probably a water quality issue. If you didn't have a filter in the tank, and it was a smaller tank, then the ammonia has probably built up and caused the loss of gill filaments. If that is the case then they will grow back eventually, given good environmental conditions.
Have you tested your water parameters? Was your previous tank cycled?
Have a look at the following links for more information.
Caudata Culture Articles - Cycling
Caudata Culture Articles - Filters
Axolotls - Requirements & Water Conditions in Captivity
As i said, I'm fairly new to this myself, so perhaps some of the more experienced keepers will be along soon to give more detailed and accurate advice, but I'd start with testing the water for ammonia, nitrites and nitrates.
Best of luck and keep us posted on your progress.

Changing the filter and the filter media will cause a significant loss in the beneficial bacteria holding the nitrogen cycle. The first thing to do would be to test the water using a liquid test kit (test strips are not as accurate sometimes). Donna has asked the same questions I would have asked and has provided some useful links. I would suggest reading through the links Donna has provided.

More water volume will help with water quality so lowering the water level will not help in this situation. As Donna has suggested, optimum water conditions will help the healing process. Test the parameters and post the readings here.

Thanks both of you! I've been watching her closely and stuff and she's already growing her gills back, check it out!! I'm going to go out and get a test kit in a few hours to be sure though!

Did you forget to dechlorinate the water that particular day? The abruptness of losing gill filaments, along with the gill appearance in your pictures would have me guess chlorine toxicity.

Elise said:

Did you forget to dechlorinate the water that particular day? The abruptness of losing gill filaments, along with the gill appearance in your pictures would have me guess chlorine toxicity.

Click to expand...

You know what, I think I did... I did the water change really really late at night and must have forgotten to dechlorinate, cause I don't see my little bottle of stuff for that out the next day... huh! Wow I really ought to be more careful

These things can happen, just make sure that you always dechlorinate your water in the future.
Your little one has survived and is growing her gills back, so everything is going to be fine.
It's great to see the little gill filaments reappearing.