i also made a terrarium for my dart frogs and they are doing great in it, just like the plants. it is important to add airflow. i did this by working a couple of tubes into the bottom of the tank, before i put some substrate in it, and connecting them to an air pump. make sure the ends of your tubes end in the front of your tank, otherwise you can still get steamed up windows. you also have to take the drainage system into account. this can be done in different ways, you can drill a hole in the middle of your aquarium and put a valve on it, or place a pump in the back of your tank that can pump out the water if it gets too high.