sick clown fish?

[Magma]

So I have 2 Black Clowns (tank bred) picked them up from Big Als about a week ago now and today I noticed on both of them the first fin on the top is becoming almost clearish in colour.

They are still eatting and swimming around just fine, nip each other a bit but not very often the QT tank is 20gal and they have lots of space to roam, theres also a bunch of LR rubble in the bottom of the tank just so its not bare.

Any idea what could be wrong with them?

Edit: pictures
(Large files sorry)
http://img301.imageshack.us/img301/5973/img7160l.jpg
http://img253.imageshack.us/img253/9428/img7161m.jpg