bubbles on silver dollars

Question
Hi, Thanks for your reply. The bubbles look like very small air bubbles. I don't see anything sticking out of them...they just look like small round air bubbles.  Some of the smaller fisk look like they are trying to eat them. I change the water about every 3 weeks..25-35%
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-----Question-----
I have a 60 gal tank that is about 10 months old with various types of fish. I have 4 silver dollars that have small white bubbles on them for the past 3-4 days. None of the other fish seem to have it. I have had the silver dollars for 3 months.
-----Answer-----
Hi Ed
What do the bubbles look like?  A bubble to one person is a bump to another!!  Sorry to sound redundant, but have to ask these questions.
Does it look like they were sprinkled with salt?
Does it look like a pimple?
Is there anything sticking out of it?
Does it look cottony?  
Or does it really look like a bubble/when you burn your finger it gets that blister?
How often do you do water changes & how much do you change?

Let me know!!

Christy


Answer
Hi Ed

Well, from your answers it doesn't sound like ich, or fungus, or anchor worms, or bacterial.  

Does this sound like it-minus the popeye(swollen or protruding eye)?

"Gas Bubble Disease:

Symptoms: Include the appearance of Popeye. It is possible to see the formation of these gas "bubbles" which could even be classified as blisters under the skin located anywhere on the fishes body including the fins. If these bubbles move to the blood stream they can be fatal.

The condition is brought on by oversaturation of oxygen in the fish tank. Specifically the balance of dissolved gases being upset by the over production of oxygen."

Taken from this link under misc.:
http://www.bluemoon.net/~tammy/profiles/ailments.html

Here's another link, with a little more info on it.

http://www.fishjunkies.com/Disorders/gas_bubble_disease.php

If this does sound like what it is, I'm afraid I really don't have much experience with it.  The few things I've read previously on it, you'll want to make sure there's enough surface agitation (like the filter's making the "waterfall" effect)to allow the gases to exchange.  

One thing I can recommend for you, start doing weekly water changes of about 20-25%.  That actually might help as well.  

I'm sorry I'm not much help, try posting with another expert.  I think his name is Chris-he seems to have a lot of experience with fish, over 20+ years I think it said on his profile.  
Good luck!  And again, I apologize for not being more helpful!

Christy