I personally used flatworm exit a few months ago to treat an out break that I had. The product worked great and I didn't experience any problems. Okay, sorry. I had one. I lost some of my red footed snails, but either than that nothing at all. My clams, acros, lps, softies, and fish were completely normal during the entire event. The only thing is that I had to do the treatment 2-3 times to completely rid myself of them, but still no experienced no problems.