They are expensive for feeders,but yes you can use them. While wild caught frogs often carry nematodes or even tape worms these can be removed from your fish by treating the tank with a combination of Metronidazole and Praziquantel laced food like made by Jungle, or simalar stuff made for discus breeders, do it every 3-4 months if feeding with wild frogs. Check the species of frog first, some are poisonous, some are protected. Don't feed with toads.