please help somethings wrong w/fish

so I check out my tank and one of my perc's has a glazed over face and is swimming weakly (or so it seems) any ideas to what the problem could be?
I am about to run up to the store to get salt to make a medication tank.
Thank you in advance!!!

 

I can't help

But im sure they're going to ask for pictures

 

And parameters, so take a water sample with you to the LFS.

 

how long have you had the clowns and how long have they been acting that way? If they are not new, any new additions? When you said glazed over face the first thing that popped into my mind was velvet. Clowns (for being as hardy as they are) also tend to carry a lot of crud,
http://freshaquarium.about.com/cs/disease/p/velvet.htm

could also be brooklynela....
http://saltaquarium.about.com/od/ichparasiticdiseases/a/aabrooklynella.htm

 

the closest LFS are *****s they put a stick in your water and say yep....looks good.
then I had them test my RODI water and and they said 20ppm.....new filters buddy...?
I am going to the more reputable LFS a little further away tomorrow for them to test it for me. Also have a bad ick problem with my dori that the same LFS sold me a bottle of herbtana to get rid of saying "this stuff is the best it will knock it out" and it didn't do a single thing to the parasite.....having a meltdown

 

Are you in Jacksonville, NC? Or Jacksonville, FL? If you are in FL there are some pretty good LFS in the area. I know of 3 off hand that are pretty good stores.