Oh good, I'm gald you found someone good. Thats my biggest problem with chain pet stores, there hire idiots. I hate it every time I go in ours and hear them telling someone, something total wrong, just to make a sale.

A tank with water like having 5 goldfish in it, not good, no wonder they got sick. Your ammonia levels was to high. Please tell me he told you to do a small water change to get it down some. Also I don't know if pet supermarket sells it but there these rocks called amio-rocks, they sell them for gold fish tanks. Get a bag and put a few in your tank, wash them first of course. They really do help keep the levels down. Most pet stores wont tell you about them, sense they are for goldfish, but we been using them for years in our tanks. It works great. The old man who breeds fish for pet stores told us about using them. Every one of our tanks has about 5 or 6 in it and we never had a problem with ammonia.

I have my fingers crossed that your fishys make a full recovery.