I had a tank that got either Ich or Marine Velvet. Not sure, but fish were dying quick. I had Interceptor so thought it wouldn't hurt anything so attempted it, and what ever parasite was present was gone. Definitely just my experience, and I am not saying it's specifically for that. Or that it will work for everyone. It works on calcium channels of invertebrates so has activity with many different organisms. Just doesn't kill everything.

