Question: How do I tell if a fridged axolotl is dead?

[Wilbur]

I noticed a few days ago my axolotl Mirio had a little bit of fungus on his gills, and the tip of one seemed to be missing (I believe he stuck his head in the intake of his cooler's pump). I tubbed him with somoe indian almond leaves and he seemed to be doing well, but then I gave him a 12hr methylene blue bath at a little less than a half dose (which I know now is a dangerous amount of time for an axolotl.. gotta hate misinfo). His gills and tail were curled, his slime coat was stained blue, and he was fairly non-responsive, so I started him on a 5 day course of gentamicin and fridged him per my local vet's instructions. He has been fridged for roughly 24hrs. Since then, his gills have become discoloured (its either that or they're covered in fungus, not certain), and he has become completely non-responsive. He won't move, occasionally floats on his side, gills arent moving, etc.. I've done everything I can for him and I just really want to believe he still has a chance and I haven't killed him by accident with the blue bath. What are the telltale signs of a dead axolotl? He isn't stiff when I pick him up (with gloves). So sorry for ranting, this is just the second time I've had an axolotl go downhill this quickly, and the first one did not survive due to poor maintenance. I want to do better this time.

 

[wolfen]

main signs would be lack of movement (during day time most movement would be gill flicks), odd posture with no effort to correct (this can be on it's side, upside down etc..)
if unsure of life tub in clean dechlorinated water at a good temperature ie.. 15°c-18°c (no lower than 10°c) put lid on tub to prevent possible escapes.
watch for movement (might take a while even if alive).