We have a 12 year old Oscar fish. He is normally very active. He stopped eating over a week ago. We have had our water tested and everything is fine there. Since he stopped eating he has taken to sitting on the bottom of the tank barely moving unless prompted. He looks like he's having trouble breathing. His color has almost completely faded. Yesterday his eyes started to look clouded over and today his belly looks a little swollen. Please help!

welcome to the site.

fine water meant nothing to us to help people... we need exact data.
amm0nia =? nitrite = ? nitrate= ? pH=?
tank size =? feeds=? filter capacity=?

though you have your fish for 12 years, that is already an accomplishment..
but cloudy eyes, swelling belly, fading color, heavy breathing; and not
eating are all sign of health problems. better get those data so that people
could get you the correct advises.

I can try to get that information. Someone from our vets office came and took a sample and then called us to let us know that the sample came back fine.

Welcome to our community, I'm sorry it is under such circumstances.

You are doing well with a 12 year old oscar, On Oscar's lifespan is around 15 years. Just like any other living creature, fish can sometimes develop illnesses, it doesn't mean you are doing anything wrong. You say he is having trouble breathing, is this breathing heavily, opening and closing his mouth constantly? I strongly suspect that your fish have some kind of internal problem. What kind of problem, I'm afraid I don't know. Let me look at my book and I will come back

i suggest you get a liquid water test kit and test the water by yourself.
cloudy eyes and difficulty in breathing is a sign of bad water condition.
any changes done in the tank lately? like cleaning the filter and media?

The water was changed about a week ago. (filters and all) We had added a carbon filter to the tank at that time and when he got sick the first thing I did was take the carbon filter out of the tank. (I thought the carbon might be making him sick)He is open and closing his mouth constantly and sometimes appears to be choking.

He died last night

So sorry for your loss.