strange clownfish colorization

[mr.limpet]

I've noticed that my clownfish's color seems to be changing. The upper portion of his body is turning darkish brown. Has anybody noticed anything like this with there clownfish.
I've had the clownfish about a month, his eating and activity levels are fine. Water in tank is within tolerances.
Thanks for any help.

 

[tuningvis]

do you have anything in there that might sting it?

 

[mr.limpet]

No, only have 1 yellow tail blue damsel, one coral banded shrimp and 1 turbo snail. I've read on this post that the dark colorization that is occuring may be that the gender is changing to female. Weird.

 

[tuningvis]

could be ... how long have you had them togeather ... and are they changing size as well?
the darker one of mine is the smaller one(male)
he is noticable darker than the female