I am getting some amazon tree boas and I have some empty 20 gallons lying around.

My plan is to temporarily house one adult amazon tree boa in one of these aquariums and stack it up right. This plan sounds good... but a big problem is that it is an aqaurium with a sliding SCREEN lid... anyone with tree boas know they need tons of humidity. How can make the lid more able to retain humidity?

ALso, since this is only temporary housing, do any of you know of any cheap arboreol cages?

Thanks in adavance.
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Starkey
Mystic Eye