More help can be offered if you give more detail. What is there set up like? Temps, humidity, substrate, what are the other tree frogs?
Right now it's best to separate everyone into their own tanks with a simple set-up. Moist paper towels, a few climbing branches and potho clippings for hiding. Get the frog in question to a vet ASAP. Any problem or abnormality can hurt your frog.
Mixing specis isn't really recomended. You run into problems with stress, parasites, food competition... only to name a few.
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Heather

ellasmommie@yahoo.com