im new, i have 2 green american tree frogs had them around a month when i got them i was told they needed only a substrate and food ect and water but as i read up after i got them there seem to be other requirements any help?

also one of my frogs seems to be severely ill it lost all its weight rapidly and wont move much looks like its struggling any help please im really worried i put him in a small tank on his own and tried to hand feed him but nothing ;.;