I think your tank is too big for a baby I got mine last august and have him in a 10 gallon and that is more than enough room for him. I have a uth under his warm hide and a lamp over the cool and it keeps the ambient at 80. If you have too big of a tank it can really stress them out cuz they like small spaces do if u can I'd get a 10 and keep the 40 until its an adult. You can also cover the top with tin foil, that should help keep in heat and humidity

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