White film covering my oscars

Question
Hello,
    My name is Keron Edmund and I have been experiencing some problems with my oscars.  After a recent water change, a white film has begun to cover their bodies, and it is eating away at their gills and fins.  I experienced the same problem with my past goldfish, and it turned out to be a ph problem.  In my oscar tank i tested the water levels and they are all perfect.  There are no open wounds on any of the oscars and i currently have 6 small oscars and one large pleco.  The temperature and everything is fine and i don't know what it can be?  Thanks for all the help.

Answer
hi keron....

to fully answer this question, i would have to know the size of the tank, as i am sure u are aware that on oscar by itself requires 55-75 gal, 2 need 90-125 gal, 3 need 150-220 gal, 4 need 220-300 gal, 5 need 300-350 gal, and 6 would need 350-450 gal minimum tank sizes.  also would have to know the kind of filtration system and food u are feeding.  i reccommend canister filtration(cascade makes and awesome caniter filter) be sure to use a filter rated at twice the size of the tank for oscars.  next is the food issue.  i feed and reccommend the omega one brand of food as it is made of human grade ingredients.  most of the other food on the market is made out of the "meals" for example fish meal and seaweed meal.  not omega one it is made of whole halibut, krill, whole seaweed, whole salmon, u get the idea.  better food=healthier fish.  then i wonder if u are using aquarium salt(available at most pet stores) use one teaspoon per 5 gal.  lastly if the problem continues, i reccommend using a product call Prima-Fix.  it is available at most fish stores and at www.petsolutions.com

hope my advice helps

good luck,

timm