you can use general cure, which has the same drug as Prazipro in powder form. Don't follow GC's instructions, instead treat as you would with prazipro- two doses 5-7 days apart (you can do a 25% water change between doses).
1. For best results, remove activated carbon or filter cartridge from filter and continue aeration.
2. For each 10 gallons (38 L) of water, empty one packet directly into aquarium.
3. After 5-7 days repeat dose of API CG as in step 2.
GC contains both praziquantel and metronidazole, Prazi is reef safe-ish but metro isn't, so if you use GC and have inverts/corals don't dose it in your display tank! If the fluke-infected fish in the display tank you may want to treat al fish nd leave the tank fallow for 4 weeks to make sure all fluke eggs have hatched and adults have died.
also #mods maybe move this to disease forum?