Is he sick?

Trying to identify of my axolotl is sick has these spots

He is eating trout worms and frozen blood worms. He eats about a half of a earth worm and a cube of blood worms daily. He skips the blood worms some days. Hes in a 20 gallon tank with a couple fake plants and hides. I admit he is not in a cycled tank because he is a rescue and I am learning as I go. The filter I had was a Repti Clear Terrarium Filter F350. It was fully submersible and a couple blood worms got caught in the filter where I couldn't see them and started to decay. They grew this white feathery fungus looking stuff. I believe its Cotton Wool Disease. I gave my axolotl salt baths for a week. and the spots are still there? I know for sure he had some in his gills but it looked gone. He does not have a filter now but I am doing 20% water changes daily. Today I am getting a 90 gallon tank with a fluval 306. The filter is used but only for 2 months. Should I replace the media in the filter? or give it a good rinse and use those ones. Would a used filter help cycle a tank faster? I really want this guy to be healthy and ready for the 90 gallon tank Also he was not eating earth worms when fungus came. Just blood worms.

The spots I can see look like iridophores and are perfectly normal and are part of your axolotls colourings. I can't see any fungus at all and would not give any furthe salt baths. Remember to test your water more frequently whilst your tank is cycling. A used filter can be good to cycle a tank if it is still in use in an established tank. If it has dried out or has been turned off for some time then it will have no living bacteria on it.

Thanks for the reply. I was looking at tones of pictures of wild axies in the last few days and had a feeling the spots were normal and im glad to have a confirmation that the gill fungus is gone .Luckily the filter was still in use at purchase and still had a little bit of the water in the tubes and filter media was still wet.