Hmm, 7 lemon tetras, 7 neon tetras, 7 pygmy cory cats and a dwarf gourami. The two schools of smaller colorful tetras will give you some yellow, orange, silver, white, red and blue. They will be active more in the middle. The school of pygmy cories give you a very active bottom to middle section with some iridescent green and some black/brown and a muted white color. The dwarf gourami will be the centerpiece with it's alternating iridescent blue and red stripes. The dwarf gouramis will pretty much move wherever he wants to. That's just one of millions of possibilites. Check out that link I posted above and just ahve a gander at all that's out there.