Does CO2 system required for a 6gal planted nano tank ?

[Susan]

I've set-up a heavily planted nano tank for my future Galaxy Rasbora residence (hopefully I can breed these pretty fish in the future). Will be adding two more plants next week, then, my tank should be fully stocked with plants I had in mind.

My 6gal tank is almost a week old (5 days), all the plants look great without CO2 setup so far, the concern I am having is do I need CO2 to keep my plants healthy in a 6gal nano tank?

This is my very first nano tank, thanks for all your input and suggestion. (Sorry abt the poor quality of my iphone photos)

1 Fluval Edge 6 gallon tank
2 Will add 6 Galaxy Rasbora in Jan. 2013 (cycle a fish-less nano tank slowly)