I use glass dishes like the kind they put desserts in you can get at any big separtment store. It works great: Tree frogs can climb glass...crickets can't. Once in a while one might get out, but it dramatically reduces the amounts of escapees roaming the tank and you can monitor how much is being eaten. I use dried sphagnum moss as a substrate. Spray the insides with water every other day or so and the sphagnum stays moist. It also gives a cushion in case of a paniced jump. You don't have to go overboard with water. Treefrogs have an adaptation that allows them to retain moisture. They secrete a waxy substance that helps retain their interior moisture...a neccesity for living in the trees. I use small plastic critter cages. I tape off the vents on the lid (don't worry, it's not air tight) and I use a humidifier which is basically an aquarium air pump tubed into a large jar of water with another tube coming out and going through the hole you usually find in the lid of these small cages. It blows humid air and helps, but it's no replacement for periodic spraying. I use this device as an insurance policy and it is very possible you could get by without it if you are religious with spraying. Sometimes I find that if I skip a few days of spraying, that the froglets go into skin shedding when I do (scrunching up and opening their mouth to get the skin to split). I use a heat emitter suspended over the cage, but not too close. The temp is generally in the upper 70's or lower 80's. When you finally move to a bigger cage, make sure you use temperature variation. I heat them up to the 80's during the day and shut all heat off at night. My frogs respond very well to this set up. Plan on keeping your froglet in this temporary set-up for the better part of a year until he gets past this delicate stage.