I have a 40 gallon tank that I use for breeding platties and mollies. I first bought 4 platties and one molly on advice from a LFS to use them as 'test fish' for my brand new tank and now I have about 60 of them in the tank (most are fry and too young for me to sell to my LFS)
Anyways, I had one outbreak of ICH in this tank and I swear it was never ending. What happened was that my tank must not have been completely cycled when I put in these first 4 fish and as soon as I started having fry, the tank 'mini-cycled', stressing out the fish and letting the Ich grow on the fish.
I tried almost everything I could to stop it, including salt, raising the temp in the tank and almost every tab, droplet, and potion on the market for Ich and in the end, my tank got down to the origonal 4 fish, one of them died (not the molly ironically. they are better off being in brackish water) and then the tank just sort of recovered.
Over the three or four months after this incident, I went through small periods of time in which I was losing fish about one a day. I waited it out though and now I havent lost a fish in about 6 months. Not to death anyways. I do trade them or sell them to a couple of LFS around my house. The money is not good, but I usually dont pay for fish food and I have been getting pretty close to breeding a half black, half yellow platty. (Dont ask my why this is my goal, but it sure is fun to try!)
So, I guess my point that you might be good to just wait a while and check out some pictures of Ich and other diseases (my gut feeling is to look up fin rot since you said they look like they were chewed on) to see if you can put a picture to what you are seeing in your tank. Then treat accordingly, but be patient and never give up on your fish. I wouldnt get any new fish though until you get this sorted out for obvious reasons.