You caught it at an early stage. That's 100% the SAME THING my midas gets every **** week. People tell me I need to clean out his tank completely, but I have a 135 gallon on the way.
Ok, right now, it's not bad at all, and at the most, it will make your fish itch a little. Whatever you do, go get some fungus eliminator of some sort from lfs. I use Jungle's "Fungus eliminator". A yellow powder. It normally cures it overnight. I wouldn't add salt.. and at most it's a tablespoon for 10 gallons. (maybe mollies and midases are very different, but it made my situation worsen).
Also, sometimes I'd just do a big water change (I normally do it weekly), and it goes away on its own. So if you're not particularly clean, that's probably it.
Edit: If it gets on the fishes eyes, it will make them go blind VERY quickly.