I don't even keep red wigglers for fear of getting them mixed up and accidentally feeding them to one of my snakes (they are toxic to garters).
But my pac loves nightcrawlers. In fact, that's about 95% of her diet due to impaction issues with other foods, and she is fine.

Coming from someone who also had to keep a frog hidden from an RA for two years; NIGHTCRAWLERS. It's the best way, unless you know a bait shop owner that will let you pick out only female crickets (they don't chirp)... He actually still asks me if I want male or female crickets whenever I come in to buy fishing bait... If your frog won't take the nightcrawlers at first, rub them gently on its lips for a minute till it gets annoyed and snaps. After a time or two, they'll recognize them as food and go right for them.
Also, the frozen silversides they sell at most Petco/Petsmart stores make great treats about once a month. I've found they are easier for mine to digest than pinkies, but still provide variety.