A month is not an exaggeration at all. I had one myself that didn't eat for over 3 weeks when I first got started in this hobby. A friend of mine had a mossy frog that didn't eat for 6 weeks after he got it. So frogs can go along time without food.
Red eyes are ravenous when they are settled. I tong feed mine so I dont have any locusts or crickets eating up my live planted tank. They snap them up right away and the female is exceptionally greedy and will keep eating. Again this is all after they got used to me one of which took 6 months as he would turn amnd jump away if i came near him with food on the tongs now he is much like the 2 other snapping it up right away.