A few reasons why I treat with Prazipro prophylactically, but am more reserved when it comes to using medications containing metronidazole (like General Cure):
1. Prazipro contains a stronger concentration of praziquantel (9.46 mg/gal) than General Cure (7.5 mg/gal). While both should get the job done, I like praziquantel a little stronger for eradicating gill flukes being it's such a mild active ingredient.
2. The other active ingredient found in General Cure is metronidazole, which is mostly used to fight intestinal worms/parasites. Metro is not as gentle on fish as prazi IME, so I don't like to expose fish to that unless I have to.
3. Gill flukes (treat with Prazipro) can have subtle, almost unnoticeable symptoms. There's nothing subtle about a fish swimming around with a 6 inch long stingy white poop hanging out of his butt. :lmao: And that's when you know you have a fish afflicted with intestinal parasites and it's time to use metro.