A port system including an implantable first fluid guiding system, an external second fluid guiding system with a connecting head at one end, a percutaneously implantable port for establishing a fluid connection between the fluid guiding systems, the port including a port casing which forms a first connecting element, and a connecting device which includes a second connecting element, wherein the connecting head is fastened to the port casing by a releasable, engagement of the connecting elements, several embodiments of which connecting elements are encompassed.