As Josh says, mold is normal, but I'm afraid you will need to put up with fruit flies as a mainstay diet unless you want to raise crickets instead, which is much more problematic. Springtails are very good accessory fodder, but they are very tiny and it takes a lot of them to fill a hungry frog. While they probably have more natural calcium than fruit flies, they are impossible to dust for other vitamins, especially D3, that is essential. You could also supplement with rice flower beetle larvae.
My family has just gotten used to putting up with escaped fruit flies. They even get into my computer keyboard, my wine glass, my ears, and have been discovered hopping around in the salad bowl. They don't carry disease, are harmless, so we just brush them aside or just eat them and pretend it's pepper. Putting a shallow dish of vinegar near each tank may capture some, and keeping a piece of fruit such as an orange slice inside the vivarium may hold them from immediate escape, but I frankly don't bother.
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Patty
Pahsimeroi, Idaho
4 D. auratus blue
5 D. galactonotus pumpkin orange splash back
5 D. imitator
6 D. leucomelas
4 D. pumilio Bastimentos
4 D. fantasticus
4 P. terribilis
4 D. reticulatus
4 D. castaneoticus
2 D. azureus
4 P vittatus
