Is there any way to create a fade effect in order to hide what isn't rendered by the camera?

Hi, I'm working on a game, and in order to increase framerate, I had to reduce the far clipping plane. However, as a result, you can see an ugly gap of sky at the places that are too far away for the camera to render. I've tried adding fogs through the Window --> Lighting setting, but it doesn't seem to work and the standard assets does not produce the desired effect. Is there any possible way to create a fade effect in order to cover this ugly gap of sky?