I recently set up a 2.5 gallon. I used a finnex fugeray clip light , I also used the fluval 20g co2 kit and added a buble counter and difuser and it seams to be working great, the cartridges are generally cheap. The plants I went with were dwarf baby tears for the carpet, micro swords, green wavy buce plants. I also went with chili rasboras and orange sakura shrimp. I have yet to recieve the flora and fauna but I ordered from aquatic arts and cant wait. Did a lot of research and this is what I came up with hope it helps.