Abstract: A port fitting for use with a barbed fluid connector includes a plug having a first end and an opposing second end with a guide outwardly projecting from the second end. An O-ring is disposed on and encircling the plug. A pair of elongated arms project alongside the length of the plug. Each arm has a first end secured to the first end of the plug and an opposing second end that is freely disposed so that the arms can be flexed by manipulation of the second end. Each arm has a catch that inwardly projects toward to the guide. In one embodiment the guide terminates at an end wall and a channel extends through the plug and guide to the end wall. An optical sensor is mounted on the end wall.