Prazipro just doesn't seem to be working, anyone try De-Los? From what it say it will even kill the eggs, see below. I've been fighting these Gills flukes for about 6 1/2 years and when it seem like they're all gone they comeback and then I get an explosion in the tank, where every fish gets them.
Fish Disease Diagnosis: For control of anchor worms, lice, gill flukes and assorted external parasites on freshwater, Koi and marine tropical fish. Toxic to sharks and snails. Do not use on prehistoric fishes such as arowanas, silver dollars, lionfish. Not for use in tanks which contain invertebrates.
Fish Disease Treatment: 1/2 teaspoon per 10 gallons. Treat once a week for 4 weeks. 1/2 pound (treats 908 gal.) If you are using this product in outdoor Koi ponds, no water changes are necessary. This product will kill fluke eggs, Praziquantel will not.