I agree, whereas it certainly is individual preference. If you like it as is, then leave it. However, if you'd like to prepare a real cool background, then do this: Get paper/cardboard the size of the back of your tank. Spray construction foam (polyurethane) on it, let cure. This way, you create a 3D background. Paint with oil-based paint and let the colors flow into each other. Use brown and green, but also bright yellow (sparingly). It'll look awesome. I do that for all of my tanks. It looks real natural.