Abstract: An aeration fitting for an aquarium including a hollow outer fitting having an interior channel, a cylindrical back portion, a cylindrical front portion having a threaded outer surface, a tapered cylindrical middle portion, and a frontwardly flared outer lip. A floating ball is disposed within the interior channel of the outer fitting. A hollow inner fitting has an inner channel, a cylindrical posterior portion, a cylindrical anterior portion having a threaded inner surface, a tapered cylindrical central portion, and a frontwardly flared inner lip. A spring is disposed within the inner channel of the inner fitting. Each of the back portion of the outer fitting and the posterior portion of the inner fitting is connectable to an air hose, and the threaded outer surface of the front portion is selectively engageable with the threaded inner surface of the anterior portion within an aperture in a wall of an aquarium.