Hello! I have a White's Tree Frog named Froggie (avatar). Lately, Froggie has been brown a lot more than usual, and isn't very active. I decided he needed some improvements - so, I got him a playmate today named Chance, and I'm looking into upgrading his tank. Currently, they're in a 12x12x18 Exo Terra set up. I'm thinking about either a 20 gallon high tank, or a 30 gallon hex tank. Which one do y'all think would work better for my babies?

Thanks for the help.