I was at my doctor's office and they had a 55 gl tank in there.It had 2 5in goldfish 1 pleco and about 6 smaller goldfish.I started looking at the tank and my first thought was they look really hungry. They kept coming to the top of the water and gasping.Then I looked closer and noticed there was no air pump or anything on the tank except an undergravel filter.I found myself looking for an air pump that had maybe come unplugged or something.And I had to keep myself from asking the receptionist where it was.It was horrible when I realized they had no air!