You don't always have to add extra Prime to dilute ammonia. It is better to use just the reccomended dose needed to treat new water that you are replacing. Doubleing the dose is for emergencies or if your tap water has an unusually high ammount of chlorine, ammonia, chlorimine or nitrite. Just use treated water to dilute ammonia to keep it from exceeding 1.0ppm. If you haven't added any aquarium salt to your water, this would be a good time to do it. It may be better to isolate the sick fish to a QT or Hospitol tank if you have one available. If not, for future use it is a good idea to have one so consider setting one up. Most people don't have one. I never used to until about 5 years ago, and it is invaluable. Anyway, salt will usually perk up a stressed fish.

Okay, I'm gonna put some salt in there. What kind..regular food salt or should I get aquarium salt? I just did a major water change...but the fish was still at the bottom when I left..He has been doing fine...just all of a sudden went and sat at the bottom..even his body and fins look okay...the water temp had dropped to about 66 to 68...Could that have been the cause of this behaviour?..but the temp is fine now......I'm really confused...

Water temp is fine for goldfish. I forgot what fish you had, but noticed a reply that you had goldfish in another of your posts. Anyway, I personally use tablesalt that is iodized and has an anti-caking agent in it. I prefer it actually to the aquarium salt ( actually just dehydrated sea water) that is another debate for another time. I would reccomend getting aquarium salt from a pet store since you are new to this. It usually has good directions on it. The only thing is the dosage. Since these fish haven't had salt in a while i would only use 1/2 a tsp. per 10 gallons of water in your tank. The next day add another 1/2 tsp per 10 gallons. I think the directions say use 1 tsp. per 5 gallons, so do this for 4 days. After the fish gets well I would reduce any more salt adding to 1 tsp per 10 gallons ( or even smaller dosage) or just don't use it at all unless necessary. If you can't find it, or just don't want to use it tablesalt is fine. Hopefully this will do the trick. I have been real busy lately so I don't check in here often. Feel free to email me by clicking my board name if you have any questions directly to me.