I have 2 large oranda goldfish in a 40 gallon tank and have had just the two of them for several years now. I recently got behind in my otherwise routine water changes and noticed one of the fish gasping at the surface, floating on his right side with frayed fins, a cloudy eye (the one at the waters surface) and seemingly paralyzed. The other fish seems perfectly healthy. I quickly did an 80% water change (aggressive, I know) added water conditioner with aloe vera, and added 2 tsp of aquarium salts. I also changed the carbon filter in the tank's filter. All the water parameters are testing well with in the safe range and the second fish is still perfectly fine. It has now been 48 hours and the sick fish does not seem to be recovering at all. He seems very distressed and unable to move. He just drifts around in the water current. I have not fed the healthy fish yet and have made sure the tank remains very well oxygenate. Is there anything else I can do to save him?