Tha air stone provides more scenery to the tank, bubbles to play in for some fish and some agitation to the top of the water, but oxygen is created at the surface, not from the bubbles inside the tank.
My fish love my airstone. They swim through it or just lounge in it. I have a long one that goes along the back of the tank. The angel fish really love it great place to play.
Speaking of airstones, I am researching info to set up my new 55 gal. I have 2 filters for 55 gal. tanks, would I need an airstone? Or would the two filters work?
RE Iceblueeyes: Unless you have an UGF (undergravel filter) you do not need a airstone to lift any water. If you do have an UGF I would get a powerhead for it. Your two filters will give you plenty of water movement in you tank.
