Backgrounds are a good idea, but to keep things more natural try a houseplant. The plant will love the light and it will look pretty, too. If you don't have a green thumb, try a Pothos (you can find them regularly at walmart or similar store). They do well in low or high light and are easy to grow.
8 tanks running now:
1x 220 gallon, 2x55 gallon, 1x40 gallon long, 1x29 gallon, 1x20 gallon long, 1x5.5 gallon, 1x2 gallon
Gouramis, barbs, rasboras, plecos, corys, tetras, fancy guppies, swordtails, ottos, rainbow shark, upside-down catfish, snails, and Max and Sparkles the bettas.