Light for 20gal planted

[GuppyLover]

I have a 20 gallon tank with a few plants in it and today I got a blue Mickey Mouse Platy, she was a brilliant shade of blue at the store but when I got her home she looked like a white fish with black trimmed scales. I got her from Wal*Mart so I'm sure they don't buy expensive lights. I have always known the lights I had weren't very good but I never really thought they were that bad. I have no idea what type of light I would need for it so help is needed. Thanks in advance!

 

[GuppyLover]

??

 

[Coleallensmom]

Really, it depends on what type of fixture you want and how much you want to spend. Check out this thread, you might find some useful information:
http://www.aquariumadvice.com/forums/f24/lighting-guide-for-a-planted-tank-141782.html

What plants do you already have?