I agree with both Melted and Disher. I personally would take the background off. I really like plain black backgrounds as it hides cords and gives depth to the tank without becoming distracting from whats actually in the tank. As for the filter, it's quite large (in size) for that tank and not only takes up a lot of valuable space but is very distracting to the eye. I have a few nano's 2-8gal and all have the Deep Blue Bio-Maxx nano filter on it. It's great because it's an HOB, has an adjustable flow rate, is clear so looks good and it can really push water around. Not to mention it is silent and very affordable, only $15 at my LFS. Other than that you could angle the rocks a little more, maybe lay one down and put another on its side. I think you're off to a nice start though and those clams seem pretty cool!
75G, 29G, 20L, 12L, 10G, 5 Nano's, 3 Betta bowls
12G Rimless Club
*Everybody has too much of something...me? I have fish tanks.*