Juvenile axolotl lying on back

Hi, I have a juvenile (~3 months old) axolotl who has been lying flat on his back for some time. The issues began a little over two weeks ago, with some buoyancy problems - floating up and tilting to one side. A few days later, the floating stopped, but he was now lying on the floor of the tank on his back. Whenever I tried to gently flip him back over, he stays upright for less than a minute before flipping onto his backside again.

After checking my water temperatures and finding them to be a bit too high, and reading through a number of the posts and guides on this forum, I decided to try fridging him. Right now he is in a small plastic tank in the fridge with just enough water to cover him, with daily water changes. The temp in the fridge is about 45F (7C). I offer frozen bloodworms to eat every day, but he only eats occasionally.

He has been in the fridge for about a week and a half now, with no noticeable changes or improvements. Still lying on his back unless I manually flip him. Any suggestions on what might be the cause, and how to help my little buddy? I've attached a few pictures for reference.

Thanks!

My little lotl was in a similar situation when I got him... had trouble staying upright and became a lot less responsive. His gills were fairly nonexistent. On day two, he seemed like he wasn't going to make it more than a few more hours, and I put him in the fridge as a last resort. He stayed in there maybe five or six days before I took him out. That's a tough call too, because it's hard to tell how well they're doing when they're in the fridge. Usually they won't eat, and they don't move any more than they have to. In my case, at least he was more frequently upright, but he didn't really look revived until I took him out.

I'm not sure what to recommend for how long to keep him in the fridge... he looks pretty thin, though they don't use much energy when they're cold (the general rule of thumb is for their bodies to be as wide as their head, though it seems like they always have huge heads when they're tiny). If yours is actually eating though, that seems like a very good sign... he's definitely still ticking. Hopefully some other folks have a better idea for when to take him out. Regardless, definitely keep up the daily water changes, and make sure to stay vigilant on the fridge temperature so that it doesn't get *too* cold! When you take him out, let him warm up gradually, and keep something on top of the container so he doesn't get enthusiastic and hop out.

You may already know all of this, but I didn't, even though I thought I'd done enough research... do you know if your tank is cycled? They're super susceptible to ammonia, and it can show up startlingly fast, especially if there are any food bits around. It gets worse as they get bigger, and any amount is harmful. Seachem Prime can neutralize it for a day, but eventually the tank needs beneficial bacteria to turn it to nitrite and then nitrate. I glanced at an earlier post of yours and I didn't see a filter or any aquarium decor. That stuff (especially the filter) can be pretty essential because it provides a lot more surface area for the bacteria to cling to. There are lots of good posts here about cycling, how long it takes, and how to avoid it crashing once it's established! Also, in addition to avoiding ammonia buildup, axolotls absolutely have to be kept below 70 degrees F... which can be dreadfully hard. The closer you can get it to 60, the better. Fans over the top of the water can help, or even putting your lotl right in front of the air conditioner as long as it's not exposed to sunlight. They like their pH a little north of 7.0, and their water slightly hard. Again, I'm super sorry if that's all stuff you already know, but I wish I'd better understood how important it all was when I got my little Kimchee.

Anyways... best of luck, and stay positive. They're surprisingly hardy little creatures. Do keep us posted!