One of axolotl's gills dying?

My axie Darwin has been an unfortunate victim of this horrific heatwave in London, I've been using frozen bottles as much as possible but i'm at work all day, and I've been forbidden from putting him in the fridge by my mother, so his tank has frequently reached pretty high temperatures

I noticed the other day that his top right stalk (top left in the image) is much shorter than it used to be, and compared to the opposite stalk on the other side. Also see my profile image which is of his gills normally. I took him out and scoured him all over for fungus but I haven't seen anything resembling the cotton-like substance I'm supposed to be looking for. He did have some white specks behind his gill (see picture) but I think that could just be sand...I can't find any images of fungus that looks like that.

I gave him a salt bath just in case but it was horrible, he hated it and I hated doing it to him so i'd rather not do it again, but is it better to play it safe and give him one?

There are no other lotls in the tank and while there are some tank accessories I really don't see what kind of accident could chop off a chunk of one of his gills!

Thanks for your help in advance!

Do you have an aquarium fan or, failing that, a small fan you can position strategically? I know you've been getting hit pretty hard with the heat there...my wife was in London a few days ago and she was complaining about the heat....probably the first time in history somebody has gone from Ontario to London in August and said it was too hot there. Mark it on your calendar. How high has the tank temp gotten?



I have to say, that does look like deterioration rather than damage, in my admittedly uneducated opinion....it looks more shriveled than cut if that makes sense.