The victims' wounds were not considered serious. Meanwhile, the teen-ager was booked on a charge of carrying an illegal firearm. Investigators say he ditched a gun into a trash can as officers chased him, but they recovered it.
Police say more than one person may have been involved in Thursday night's shooting, and they are continuing to investigate.
The Krewe of Chaos floats were stopped to let ambulances through. After that, the parade resumed. It was one of three on Thursday night.
Tuesday is Mardi Gras, or Fat Tuesday. The advance celebrations are known as Carnival.
