First you will need to dump out the bark, throw away the light, and get rid of the wire top. Then you will need to buy a glass top, coconut substrate, and maybe a tall fake plant. The substrate should stay fairly wet like a chocolate cake, but not sloppy wet. Keep the water dish on the cold side of the tank, unless you want to refill it every 20 minutes. keep spraying your frog lightly a few times a day. With the glass top, you will not have any problems with keeping the humidity up, in fact there will be condensation on the glass all the time. This will also solve 2 other problems; light and temp. You will be able to keep the temp/humidity under control by making a small space in the top by sliding the glass back a little. Too hot, slide it back to make the space bigger and smaller for warmer. Sense the glass is totally transparent, the light in the room will be enough light if kept on for 12hrs per day. I really hate heat lights because they dry out and kill frogs easily, make it difficult to maintain the correct temp, and cause their eye sight to fail over very little time. I guarantee that his appetite will return if you take my advice. Make sure he gets his calcium sense he is a growing frog.