spots on clown fishes

[Samw]

Yes, I've seen this before. But I don't know what it is. I was given a clownfish from someone that had black dots all over it. It came from a 10 gallon tank with PC lights and no skimmer and some surface scum. In my tank, the fish's black dots have gone away over time. I can't tell you why though. The difference is that my tank is skimmed, has a hosting anemone, and the fish has a varied diet.