Welcome aboard.
Most likely we are dealing with a poisoning situation. Different amphibian species should never be housed together, because they poison each other. Bufonids such as the American toad are toxic and so are fire-bellied toads and kassinas.
Other problems I see with this enclosure are dumpys or White's get big enough to eat the other frogs. You have frogs from for different eco-zones, neoarctic, palearctic, Ethiopian, & Australasian. Maybe a fifth one as I have no idea what exactly a brown treefrog is. If its a Polypedates leucomystax, then you definitely have fifth zone represented. The problem with housing animals from around is they bring with them pathogens and parasites from those zones, a cross-infection is highly likely. Plus a lot of these frogs come from different kinds of habitat, so its impossible to satisfy all there needs.
That being said they need to be separated into species specific enclosure immediately.