I have a fish and invert tank, and have had problems with marine ich. The problem wiped out my first stock, and my second one is doing OK, although the problem persists with some species. My Coral Beauty gets it on occasion, but my cleaner shrimp takes care of it, the fish is fine. I also have A true Percula, A Firefish, and a Green Banded Goby, all healthy. My Neon Gobies are covered with Ich, and my Royal Gramma died from it. I want another Royal, but don't want to get it until the problem is under control. Inverts in the tank are some crabs, a Peppermint shrimp, Cleaner Shrimp, Turbo Snails, Sand Sifting Star, and an Arrow Crab. Suggestions would be helpful. I have been thinking about a UV Filter.