Welcome aboard. You can pretty much keep mantellas the way you keep dart frogs, heavily-planted, highly humid enclosures and a diet of fruit flies and other small insects. What kind of frogs do you have besides the painted mantellas? I have -
4 Bombina orientalis, fired-bellied toads
1 Anaxyrus debilis insidior, western green toad
1 Chaunus schneideri, rococo toad
2 Ollotis alvaria, Colorado River toads
1 Dendrobates tinctorius, blue poison-dart frog
2 Dendropsophus leucophyllatus, clown treefrogs
1 Hyla cinerea, green treefrog
1 Sphaenorhynchus lacteus, greater hatchet-faced treefrog
2 Litoria caerulea, White's treefrogs
4 Agalychnis callidryas, red-eyed leaf frogs (+ a ****-load of tadpoles)
1 Phyllomedusa hypochondrialis, tiger-legged monkey frog
4 Dyscophus guineti, southern tomato frogs
3 Phrynomantis bifasciatus, red-banded rubber frogs
1 Phrynomantis microps, red-backed rubber frog
3 Rhacophorus reinwardtii, blue-webbed flying frogs