how big is the fish tank i would say at least 20 gallon for goldfish depending on what kind they are can get up to 12inches why don't you pick a different fish like fancy guppies they are very pretty unlike goldfish and they are smaller to a LOT smaller so you could get a whole lot of them and chances are they will breed, that would be cool and you would also need a filter and then.....that sounds good you may want the heater, yeah i think you will
