Im looking at planting my tank its only 20 gallons and it has 2 plecos a bumblebee cat a raphael cat, golden ram, and a golden wonder killie. What I am wondering is what would be a good way to do it. I want to largely cover the back of the tank instead of using those picture things. I also would like good coverage over the top. I dont want any serious growth at the front of the tank though. What should I use and will I need a CO2 injector to make it work?