If it is ick, my advice is oxygenate heavily with airstones or skimmer (Skimmer is better because it doesn't produce salt spray). Ick is not hard to beat. Fish can survive it.
My tank has ick from the very beginning and most of my new fish seem to get it when I introduce them to my tank. However, they all survive and become immune to it on their own without treatment, garlic, etc. Maybe cleaner shrimps help a little, maybe not.
Here is Moo when I first got her
Even Moo kicked icked and lived happily ever after for years. Before I bought my skimmer, all of my fish got ick and died. After I got the skimmer, ick never killed another fish. At least, I've never seen a dead fish in my tank with ick since then. Ick is still in my tank.