I have a bubble wand which was given to me by a friend and wanted to know if it is really beneficial for my 15 gallon freshwater tank. I have an air pump where you can adjust the bubble flow accordingly. Wanted to see if it was good to add to a tank. I have good surface movement for oxygen exchange and the fish appear to be breathing normally and figure maybe this would enhance their livelyhood. Is a bubble wand really beneficial or is it more for show?