Do you have a hospital tank setup?
May be a good thing to start setting up if you suspect anything.
Have you added anything to the tank lately?
Do you have your tank parameters?
In the future, post these types of messages in the fish disease section of the forums and the fish experts will probably get back to you.
Also, here is some helpful information for posting this kind of stuff; I found the fish medics would get back to me faster if I had the information they needed.