So I'm upgrading from a 20 high to a 29 today. I'm so excited!!! I know it's not much, but I am still happy with the upgrade. I have plans to do a pair of apostogrammas (flame maybe) and some schooling fish. Haven't decided on cories or otos though.
20 gal hex: 3 X Guppy,6 X Chili Rasbora, 2 X Dwarf Cory Hasbrosus (soon to be 4), 1 X Female Betta Imbellis
20 gal tall:currently cycling, soon to be re-aquascaped