Ich isn't going to clear up on its own, it goes through a cycle and may appear to go away only to come back and hit twice as hard.
You say that there is no ammonia for the last 2 days, was there ammonia present before then?
Do you own a qt
tank? If so, I would set it up and move him to it. If you are sure you saw a parasite, begin treatment immediately. I would suggest cupramine, that would cover you for ich and for velvet.
If it were Brooklynella, you would see an obvious slime coat. It almost appears that the skin is coming off with a spider web appearing slime on his body. Anything like that?
Just trying to troubleshoot a bit here, but definitely get him to qt
Any other fish stock?