Clownfish color changing?

[Pico Perfect]

I have two baby clownfish (from the same clutch) in my nano tank. They are doing well, healthy, eating well, behaving well, but I have noticed that both of them are starting to do some color changing. In the orange portion on their sides, they are starting to get more and more black spots. See attached pic, sorry it was the best I could get tonight. Is this something that is happening as they mature? They are both doing it and I don't think it's being caused by the tank. I'm hoping a breeder here will be able to shine some light on the increasing darkness!

 

[vetteguy53081]

Not a color change but likely a sting from anemone or hammer coral
Maintain good water quality and diet