When you are saying 6...something, doesn't register. Could it be lower than 6? If so It sounds like your water is too acidic. If water parameters are bad the fish will be steressed and will lead to disease. If there are other Oscars in that tank, chances are that the bio-load is causing the balance of your aquarium to crash...thus the acidic water.
There are a couple things that could be wrong. The white Feces could be the first signs of the fish having "Hexamita" which is an intestinal parasite affecting the lower intestine. Oscars ar especially prone to it. To treat it you need to do a combined exposure in both the food and the water with a drug called metronidazole. the fish should be removed from the tank and placed in a quarantine tank. In a pinch a 10 or 15 gallon tank will suffice. Follow the instructions for the drug treatment.
One other thing it could possibly be is constipation...but since another fish died of the same disease, I would say it's the latter. Get the fish to another tank to treat or you will loose the others. You can get metronidazole at one of the local pet stores.
The salt won't hurt...but it won't help either.
There are a couple things that could be wrong. The white Feces could be the first signs of the fish having "Hexamita" which is an intestinal parasite affecting the lower intestine. Oscars ar especially prone to it. To treat it you need to do a combined exposure in both the food and the water with a drug called metronidazole. the fish should be removed from the tank and placed in a quarantine tank. In a pinch a 10 or 15 gallon tank will suffice. Follow the instructions for the drug treatment.
One other thing it could possibly be is constipation...but since another fish died of the same disease, I would say it's the latter. Get the fish to another tank to treat or you will loose the others. You can get metronidazole at one of the local pet stores.
The salt won't hurt...but it won't help either.