Why is my axolotl lethargic?

[AxYlOvEr]

I'm sorry to hear that. Rip Mika. I dont think it was fungus i think what you saw was mika decomposing they do decompose quickly. You did all you could. Mel x

Thanks...yes I thought it might be him decomposing too.
I wonder what killed him though? He was perfectly healthy until a couple of days ago. I tested the water afterwards and it was fine.

 

[AxYlOvEr]

Sorry to hear it. You definitely gave it your all and were a dedicated owner.

Thank you.
I still wished I'd fridged him earlier, you know, BEFORE he died.