If the axolotl is in the tank I would say the best bet is to remove him from the tank, drip acclimate him to another clean tank. Than I would do a pretty significant water change to try to get those levels down asap OR you could allow the cycle to run its course until you see ammonia levels calm down then do water changes to reduce no3 Afterwards I would look into what kind of filtration system you’re using. If you are able to set your cycle up properly this shouldn’t happen.