Not being able to see the little one it is hard to know what size you mean when you say little.

When my babies morphed I fed them springtails and other tiny bugs I caught with a net in the tall grass of my field (I live on a farm).
Then I fed them flightless fruit flies.
Now that they are about big enough to fit on a nickle, I feed them small isopods, baby roaches, and pin head crickets.

I like keeping my babies on paper towel and I keep a towel over top the entire container because the little ones do freak out easily. But being toads, once they know you are the food source, it's very likely they will calm right down and expect food every time they see you.