First off, make sure the smaller tree-frog not only is big enough not to be eaten by the larger frog, (If the smaller one fits in-between the eyes of the larger one, it's time to move him/her!) and second, make sure they're the same species. Pet-stores are infamous for mixing species, which is bad, and best left to experts, and some things just should never go together. (Snake and toad for example, or tiger and gazelle for another) First off, for taming skittish animals, do NOT hold them or bother them in any way. Put their terrarium in a hall-way, or a living room, or a bed-room, so they see you as a part of their environment instead of a vicious predator it sees you now. Eventually graduate to feeding them night-crawlers, (A good staple food btw) or dusted crickets and walking away, feeding them night-crawlers or dusted crickets and watching them, and finally, hand feeding or tong feeding. It won't see you as a threat, and it will probably beg for food when you walk by, (Which is adorable too) and will be the start of a good relationship with your frog. Here's a care-sheet: http://www.frogforum.net/content.php...toria-caerulea and I hope you and your frog grow to like each other!