Clown Fish Liver Spots?

[intarsiabox]

One of my clowns has some light brown shadowing in little patches under the skin. It looks like liver spots on a person. The fish is behaving normally and it doesn't seem to be bothered at all by it. It is also 6 years old. Does anyone know what it might be? Hard to get a picture as it won't stay still and it is only on one side of its body. I added a few new corals from frag fest but no new fish for months.