I own more 20 gallons than any other size fish tank. I have two styles, the 20 gallon standard and the 20 gallon long. This is my top 5 list of stocking ideas for a 20 gallon fish tank.
Not all of these fish are mine. The ones that aren't either came from:
April's Aquarium
or
Fish Addicts Langley
0:00 Intro
0:34 My Tanks
2:14 Molly's / Swordtails
3:27 Corydoras
4:23 Dwarf Cichlids
5:20 Bristlenose Plecos