i really want a plain black or dark blue background. i have seen a lot where it looks textured or wavy. i assume this is like a fabric or something? something else i thought about was just like a large sheet of paper or board or whatever, but i really don't know where to get something like that large enough. i could get several small sheets of something but i'd rather it be seemless. right now i have one from the store and it is stones and plants and what not. when i switched from bright blue to black gravel the fish' colors just popped. i want to get the whole thing darker. just looking for pictures of what you've done and some suggestions. thanks!