Is a 17H*20L*18W cage alright for one peacock chameleon? I know that the cage is supposed to be tall, but because of the way my desk is made, it cant be any taller than 17 inches high.
Have you kept chameleons before? The reason I ask is that because undoubtedly peacock AKA weidersheimi AKA T. Perreti/ serratus are one of the most fragile of all chameleons and wouldn't recommend one with out extensive experience. The combination of temp, humidity and air movement isn't something even advanced people understand with these. I've been breeding them since 2000 here in Seattle and would not recommend them to anyone as a pet. There is a reason so few are sold as CB.
The LLL video on utube is showing you the fastest way to kill these. Probably the worst chameleon care video on the net. I've bought WC peacocks from LLL and they were the walking dead because they were sooooo dehydrated.
Your cage sounds small in my opinion eventhough it's a small chameleon. 18x18x24 is the minimal size I would use. Also hydration is very very important with these but too much will cause RI's. I don't use a spot/heat light with these since they don't bask like other chams.