I am still treating Ich, and I know how much of a pain this is. I am currently using the "hot salt" method without problems to my fish. However when I tried using actual ich medecine I had a total of five deaths and a suicide (three pictus cats, three goldfish, one neon tetra from the 18 tall). ALL of these were because of the medecine. Only one fish died from Ich, and technically it died from a secondary infection. To prove the medecine was to blame only one of the three pictus had visable Ich, yet two died within six hours of applying the medecation. The third died six hours after that. Then I removed all decorations from the tank, did a 75% water change and reapplied the medecine. Two days later one goldfish was dead in the tank and another dead on the floor (I can't find a cover-glass anywhere and the cost of a hood is extortion).
Following that disaster I drained the tank, sterilized the tank with 200-degree salt water and began using the heat and salt treatment. My heater won't hold the water above 85 degrees but no new ich has appeared in a week and a half and I have had NO deaths since then. Thanks to the forum for that.