Hi. I don't know much about frogs, but you are right on the pet store being wrong... as usual. So I searched for the typical frogs they sell in pet stores which is the dwarf african frog, and I found a possibly helpful website for you. Let me know if this helps, until then... I'll promote your post. Maybe someone with experience can help you out with the food items.
dwarf african frog

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Phishie

"An ounce of prevention is worth a pound of cure."