There's a sticky here written by RD, about "Hexamita", which is what your fish have. Treat them now while they're still eating. Fish that small, if they get so sick they quit eating, are gonna be hard to force feed.
The sticky is in the beginning of this forum, or the diseases forum. It's very good, I've used it myself, and it explains how to use Epsom Salt solution, what it is, how it works, and why you should use it.
Also, there's an NLS pellet called "Hex Shield"--it's epsom salt, and some other med's, too. A bag of Epsom salt is cheaper, it works, and it's at the drug store right by your house--so I just use that.