Got it!
plastic tubs should be not really see through, right? Is there any decor for a guy to hide under? Even 5 gal for a tiny guy like that might be scary.
So if you don't have it, put a plant of sorts. It would minimize the space and provide smth to hide under.
next- leave them be, don't do anything at all with a tank or with a frog for a day, and then get him small crickets (2-3-4 per frog). Oh another q regarding tubs - do you need to slide them out to get an access to mist/feed/etc? If you do - you need smth different. These kids might not be happy with constant earthquake. You need smth stable, you lift the lid, get crickets in, close the lid, don't move the tub.

The idea is to make them feel safe and hunt on their own. Also, frogs pooping is a good sign, means that they ate something.