23 C is at the high end axies. That, combined with other issues could be causing the current behavior, even is it is used to that temperature.
How often are you changing your water, and how much? Nitrates build up and axolotls are sensitive to them (hence, the reason you should do water tests.) Nitrates are associated with fungus problems too.
==> I strongly urge you to test your water. Otherwise we are going to keep thinking it is likely a water problem, since that is so often the case. If it isn't a water problem, you will get better advice if we know it isn't.
Question: Why is your tank that warm? Usually tanks will run a few degrees below room temperature due to evaporative cooling? (The real question: you don't have a heater in there, do you? :happy
Regardless of the cause of the strange behavior, your axolotl will probably be helped if you can drop the temperature in the tank. The safest way is to have a fan blowing across the surface of the water. And in the winter it has the additional benefit of humidifying the room a bit. :happy:
Frequent water changes are also recommended, because even if it isn't the water, keeping the water as fresh as possible will also help your axie.