How many fishies! =]?

You need at least 20 gallons for 1 goldfish, even that is pushing the limits, sorry. Goldfish get too big. Yea, that sounds like about 15 gallons. Keep in mind that is 15 gallons measured from the outside of the gl with no decor. So when you account for the width of the gl, plus gravel, decor, and fish, which will all displace water, you are really closer to 11-12 gallons.