when I was still fairly new to the hobby I picked up longnosed butterfly fish. I went in 2 days prior and he had it in but it had ich. he said he was in the process of treating it and should be clear in a couple of days he said it only take about a week to kick ich (bells should of went off right there but) So I bought him and 2 days later fish started dying. well make a long story short the only thing that made it was my clown. I think in total that one dammed fish wiped out about 8 fish. I went back and chewed the guys a$$. But lesson learned