illness in my oscar

Question
hi,my oscar is about 5 yrs old and shares 100glln tank with picasso. oscars left eye recently glazed over and started to bulge.today is much worse. his right eye has good color but is a little bulged . what do you think?

Answer
Hi Mike
What kind of fish is picasso?  I know there's a picasso triggerfish, but those are salt water, so I'm going to go ahead and assume picasso is another oscar fish.  

Does he show any other symptoms, like not eating, not acting right/normal?  Does he look swollen?  From what you've wrote, it sounds like it's probably popeye.  Popeye isn't a disease really, but it's kind of a symptom of something else going on.  That can range from a bacterial or viral infection, parasites, poor water quality, too much nitrogen in the water, etc.  The list goes on.  

I found a link, has some good info explaining a lot of the more common causes and treatments of it.  Some parts are a bit confusing to understand, but overall it sounds like a good article.

http://www.flippersandfins.net/pop-eye.htm

How often do you do water changes?  I recommend doing water changes once a week, of at least 20-30%- depending on the size of tank, and amount of fish. If you're not doing this, I'd suggest checking your water parameters with a test kit.  Ammonia and nitrites should be 0 ppm, and nitrates should ideally be under 20 ppm.  If it's not showing those figures, then that could be what's causing it.  Immediately do a water change, and continue daily until you reach those figures.  The weekly water changes will keep it at that level.  

What kind of filtration are you running?  I always recommend to over filter-especially with oscars.  A tank that size, your filters should be putting out a minimum 1000 gallons per hour, but I'd go higher then that, even up to 2000.  Do you have a canister filter?  If not, I strongly recommend one of those as well.  Those are excellent for providing chemical, biological, and mechanical filtration.

Do you feed feeders to the fish?  It's really not recommended to feed feeders-unless you breed them yourself, and clean the tank up well afterwards.  Oscars are such messy fish.  The pet store feeders are usually full of diseases which can spread to your tank.  Oscars also need a varied diet, good pellet should be the main staple, shrimp, bloodworms, beefheart, crickets, worms, almost anything.  I've even given mine a little tuna fish every now and then.  

I'd recommend if you don't have one, getting a smaller hospital/QT tank.  Move the fish to that tank to treat.  Any antibiotics that you use, will most likely kill off your beneficial bacteria in your tank, causing it to re-cycle.  Plus, it's much cheaper to treat a smaller tank than a larger one.  You could also try using antibiotic food for bacterial infections-if he's still eating.  I'd say the water changes will probably be one of the most important things though.  Try the above stuff and see if it helps any.  If not, you can get back with me, and we can figure something else out.  

Good luck!!

Christy