Hey hey! Black does a really awesome job of bringing out color in your betta, but can swallow your tank if you don't add any accenting colors to mix in with it (lol at my small bit of interior design college course history)!
Thank you white! Both tanks aren't actually exactly as the pictures show at this point. When I took the picture for the 5.5G, it was at night. The lighting is more of a Yellow color, but my boyfriend had the TV going to it's light was just enough to turn the actually sea-weed green rocks to blue. /facepalm. Whatever though. Haha.
As far as the 20G goes. I recently had a bacteria bloom with the fake plants (all except the log and the fake plant within it) so I had to take them all out. Now there is all real plants growing in it. Once they grow out more I'll update with more pics. May not be for quite a while, though. My LPS keeps a pretty nifty 50G in the back of their store that they let me check out all the time, though. They showed me a plant booster that they put in their tank to boost the growth of their live-planted tank, so maybe it won't take as long. (: