If you can get to a reptile show they usually have small horn worms which are small nontoxic if captive bred very nutritious little critters that offer more calcium then several night crawlers Great Lakes horn worms can ship you 100 horn worm eggs for around 75 if I remember right and they sell their food too. Horn worms are about an inch so frogs can rip them up easy and their abut as squishy as a wax worm. Other good foods I can think of that you might find online is fly larvae called spikes and if you grow them in a jar to adult flys refrigerate the flys release the stunned flys and let the frog go to town with flying prey. And the worms will need chopped up till their close to full size I feed a frog that big bug only equal to the size of its mouth or it needs chopped up sand by mouth size I'm talking width and of the mouth to inhale them quick till they learn to bite and hold or swallow their prey down.