I just Googled the dimension of the 20 gallon long I currently have Froggy in and I believe that's plenty of space for him. It's not like he's a tree frog and needs vertical space and that much hopping room. A 20 gallon long measures 30 1/4" x 12 1/2" x 12 3/4" or so, so the one I'm looking at above would be MORE then enough space for him. I think I may go for it if I can find one at a decent price.