"Rosy Red minnows are mostly sold as feeder fish in fish stores. Rosy Red Minnows are the fish that you'll see 500+ packed into a small tank. Because of these conditions, they are often disease ridden - fungal infections, bacterial infections, and parasites. They come in different color variations - rosy reds being pink, and the natural fat head color of brown."

Source

Live foods always carries risks. One sick fish can fed to a frog can equal a dead frog. Fish are known to carry all kinds of parasites/disease and there's no way to know it until it's too late.

Sadly the moral of story is that people shouldn't feed these frogs live fish unless you breed them yourself and even then it still carries risks. Rosies are also not suitable food for your frog and contain thiaminase which is known to carry long term health issues.

In the future you may just want to stick with safer foods like pellets and if you want to feed live foods maybe stick with earthworms, crickets, dubia roaches, ect.