My red eared sliders color?

My red eared slider is about ten years old. It's "red ears" are fading and it seems the rest of its colors are as well, not drastically of course. He (or she) seems healthy but I was wondering if there's somthing more I should be doing to help keep him healthy. I have a uv light and a heating lamp so it's getting good "sun". Is a little fading natural?