Very sick oscar

Question
Hey there PLEASE help me iv got 2 oscar in a big tank and the past few weeks one of them is very sick....It has gone off food it has been laying on the bottom of the tank and not really moving unless the other one get him up...And is also looking very bloted and is breathing very weird i cant tell the sex...We have checked the water and thats all fine...We have wormed them out and turned the lights off in the tank please help me katie

Answer
Katie,

 What size tank are they in? What are you feeding them?

Let try and figure out what wrong by trying one thing at a time. Lets try treating him/her for swim bladder. This is caused by two things, over feeding and bad water quality. Let put him/her in a salt water bath.

I teaspoon of aquarium salt per 1 gallon of water. I am hoping that you have a hospital tank that you can do the bath in. Depending on the size of your Oscar you will want to get a bucket to give the bath. Leave your fish in that water for 15 minutes watching him/her the whole time so that if a problem arises you can remove the fish immediately from the salt water bath. After you give the bath, place the fish in another bucket with the right amount of water and fast him/her for 3 days. On day 4 thaw a frozen pea in warm water, shell it and feed your Oscar the inside of the pea. Do this for a few days and see if it gets better. If after 4 days, nothing has changed, let me know and we can try something else.