Former Mayor Ed Koch, who was released from the hospital on Saturday, returned there yesterday.

Spokeman George Arzt said Koch’s doctor, Joseph Tenenbaum, decided he should go back for further treatment of fluid around his lungs and to deal with complaints about shortness of breath.

Koch, 88, was released from New York Presbyterian Medical Center after a weeklong stay, in which doctors had treated the same ailments.

He also checked into the hospital for a respiratory infection in December and for anemia in September.

A documentary film about his life opens here on Friday.