A baby may very well go for ants. Some places sell harvester ants as feeders. Mainly for species like Horned lizards but a baby frog may take them or darts. I believe ants give off a bad odor or sprey something when they feel threatened of im not mistaken so some frogs may shy away. Or are they just spicy? Cant remember. Still seems like more of a hastle to farm ants they can climb out of anything so your enclosure would have to be 100% sealed. Plus the effort of licking them all up wouldnt seem worth it for the frog.