Hi just reading through this thread again but Prazi-pro and praziquantel are two different medications. praziquantel does have Prazi in it but it also contains another medication I can not think of it off the top of my head too many things running around in there right now. so yes Prazi-pro normally does not affect flat worms but it can in high doses the bottle advises it treats:"flukes, tapeworms, flatworms, turbellarians." this comes right off the bottle. You may have to use a double dose for flat worms I don't know as I have never had them and never treated for them. I had a fish come in and after QT and was in the tank the fish started showing signs of flukes. I get mine out of the USA in 4 oz bottles so I don't order often only once in 1.5 years I got extra for a couple other people. and I still say it was flukes..

Bill