well you are in aussie so he probably wont be eating due to temperature stress.
put him in the fridge (the fridge must be above 5C, if not let us know) in a food safe container with enough water to cover him. put a lid on and wrap the container in a towel (this is to stop the light blinding him). you need to keep a bottle or two of water with him in the fridge (dechlorinated) so when you do complete daily water changes the temp is the same.
the mould you describe would most likely be fungus. do cure this you need to do salt baths 2-3 times a day.
fill a container with enough tank water to cover your axie and add one tablespoon of aquaraium salt (not table salt, it has additives like iodine etc) to each litre of water. stir it up well and when its all dissolved net your axie and place him in it. remove him after 10 mins as the salt will hurt him if hes in there too long. place him back in the tank.
if he has a fungus while he is in the fridge still do salt baths, just make sure its the same temp as the fridge water.
offer your axie food daily when in the fridge, smelly food like bloodworms are a good idea. he will not eat much in the fridge as it slows down their metabolism. this is why we put them in there while medicating as they often dont eat and can starve.
have a read of
www.axolotl.org, you may find something of interest there. hope this helped!
He hasn't eaten for what I think are weeks! He is really skinny, to the point where I can see his ribs!! 