Illness/Sickness: Flosting Axolotl

[DiegoMorRam]

I need help with my Leucistic axolotl, she’s been floating since New Year’s Eve.
I read that the cause of floating might be constipation caused by rocks, food.
I usually feed them with pellets, tubifex, fish, minnows.
I tried putting her in a tub with shallow water for some days, it actually worked and she made to floor of the aquarium, but at the next morning, she was floating again...
She eats normally, she’s always hungry, I feel desperate, because del she’s the only one of my axoltls that floats...
I’ve read that a possible solution is to put them in the fridge, but I’m not sure...
I really need help

 

[NexSocius]

What substrate is she on, and how long is she?

How long has it been since she did a poo?

If she is on sand, sometimes they can swallow sand and get impacted. I have a rescue who had that problem too.
Once you answer the above questions I can help you further