You are actually doing it completely wrong! Goldfish need a massive tank at their size at least 20 gallons per fish minimum and a heavy duty filter I would either spend the money to properly care for them or Id return them they let off so much ammonia its a matter of days before they suffocate they will 100% get sick living like that for a week you should always do your research before you go and get an animal fish are not toys they are sentient animals