I am waiting on a shipment that will make my 20g High tank considered "densly planted" I have 1 large sword, 1 large camboba, 2 medium roseacea (can't think of name off top of head) plants, 1 planted driftwood, 2 bunches of moneywort and one moss ball. I have 12 fish in the tank and 4 ghost shrimp. Should I worry about co2 or fertilizer? If so what is recommended? Where is the best place to order?
Thx again

You have enough fish that fertilizer shouldn't be an issue.

I've never used fertilizer in any of the tanks that have plants and they all seem to do just fine.

A 20 high is small enough that you could use Flourish Excel to get the carbon. As SF has said the ferts will come from the fish waste and food waste.

What is your lighting? Swords are heavy root feeders. Root tabs work well with them. I know a lot of people that use 2wpg over 20 gallon tanks with most of what you have and they use no ferts and their tanks are beautiful.

I have 65W 6500K full spectrum florescent lighting in my tank. Think I will do okay without ferts? I also don't wanna be fighting algae blooms all the time

You have 3wpg so you have enough light for those plants. It's always good to add some ferts when you have a heavy planted tank. For over 3wpg I'd be adding Co2.

I would add CO2 or excel as well. Watch the plants growth, they will tell you if they need ferts or not.