it was just the one and i figured if i turned the temp up mabye it would go away on its own but i guess i made a terrible mistake
i did for the time do lots of water changes and use melted salt though
That's really sad, but don't beat yourself up too badly. We all make mistakes in the beginning.
Keep in mind, for the future, high temps do not kill ich, high temps only speed up its life cycle. (Well, extremely high temps kill it, but will kill your fish, too.) The reason people increase the temp is to speed up the life cycle of the parasite and make the treatment process quicker. But if there isn't adequate medication or salt levels in the water once the temp is raised, then all you get is an explosion of the ich population in the tank, which can quickly kill the fish.
Keep in mind, too, ich does not go away on its own. It will only get worse until treated. Your tank is still infected with ich. Even if you can't see any white spots on the fish that are left, they'll come down with it eventually. Plus, you can easily transfer the parasite to other tanks on your hands, your water vac, etc.
You ought to start a more aggressive treatment in the tank you know is infected, and keep an eye on the others. I hear that salt works well. For me, when one of my tanks had ich, I followed the instructions here:
http://www.aquamaniacs.net/forum/cms_view_article.php?aid=27
There's also a great explanation of the ich life cycle at that link.
Don't give up! Ich IS treatable!
