I am guessing that maybe the large enclosure is stressing the cranwelli out. They feel more secure in smaller enclosures. And just for the record, they have a rep for this kind of thing due to owner issues. Dechlorinated water changed on a daily basis......proper foods...proper temps & humidity are essential to the frog'e health & well being. Crickets, roaches, earthworms, guppies, mollies......these are great food sources for the frog. A squirt of liquid calcium in it's water dish every 3rd cleaning will help as well. Food items should be dusted with supplements at least every 3rd feeding (but not the same day as the liquid calcium in the water). The larger enclosure will be great once the frog is closer to adult size. They are nocturnal and lights & incorrect temps can make them stop eating as well.

Just woke up and am not quite awake yet, so if you have specific questions or need me to clarify anything, just let me know!