A coupler for coupling a first fluid delivery device to a second fluid delivery device includes a base adapted for mounting at one of the opening of first fluid delivery device, a locking member coupled to the base about the base's longitudinal axis, with the locking member being movable along the base along the base's longitudinal axis between a locking position and an unlocking position. A connector member having a body adapted for releasably mounting at one of the openings of the second fluid delivery device is releasably engageable with the locking member and with the base wherein the fluid flow passageways of the base and the connector member are in fluidic communication. Further, the locking member is biased toward the connector member to thereby engage the connector member with a first force when fluid is flowing through the coupler and with a second lower force when fluid is not flowing through the coupler wherein when no fluid is flowing through the coupler, the connector member may be disconnected from the locking member by simply overcoming the second lower biasing force.