Question
how often do i need to have an airstone in my tank?
how often d i have to clean out my filter?
thanks, stephanie

Answer
How big is your tank?  How big are the goldfish?  I suggest having an air stone in the tank all the time.  I do weekly 50% water changes on all my aquariums.  If your tank is not overcrowded, that may be enough.  If the tank is tiny, it may need water changes more often.  I clean out the filter (rinse) it (just the mechanical part) with the weekly cleaning and change most of them every two weeks.  You don't want to bother the biological portion of your filter.  Some filters don't have all three kinds, or part of the filter does more than one job.  For example, good bacteria grow on floss that also is a mechanical filter.