I assume that, being frogs, they're insectivores, but what insects would be a good diet for them? Would a diet of only crickets be okay, or would I need to feed them other types of insects as well?
I don't have any experience with this particular species, but I do currently keep some other frogs. This article confirmed what I suspected about their diet; crickets are the best thing to feed them. Sprinkle some reptile vitamins on the crickets before you give them to the frog.
If you've never used crickets as live food before, you might want to check out some of the other cricket questions on this site: