I have a 15 gal column. So the "foot print" as in the bottom of the tank is relatively small compared to the water column's swimming space. i.e. limiting stocking options. Certain fish hang in the middle i.e. Neon Tetras (but they need to school to thrive so you need 6 or more) & others hang out on the bottom like Cory Catfish. Those are fish I have & there are different combos based on water type/environment, aggression, etc!
I started w/ an Amazon Sword plant, then added Anacharis & just added Wisteria. I use Leaf Zone liquid fertilizer, have gravel & run my lights 10hrs a day. It's all doing great. Lighting is a important consideration. There's plain fluorescent bulbs, there's full spectrum, T8, etc. I'm just learning but make sure you've got the right light! good luck!