A fluid cartridge for mixing and dispensing first and second fluids includes a housing, a piston unit mounted in the housing, and a mixing nozzle. The mixing nozzle includes a first portion releasably attachable to a distal end of the housing and a second portion located distal to the first portion. An internal fluid passage communicates between the first and second portions. A static mixing element is located in the second portion and a distal dispensing opening communicates with the static mixing element. A tubular fluid separator element is located in the first portion and defines first and second flow passages. The first flow passage is a central passage and the second flow passage is radially outside of the first flow passage. The fluid separator element maintains the flow of the first fluid separate from the flow of the second fluid in the first portion of the mixing nozzle.