A pump, in particular a blood pump, with a proximal and a distal end and a pump housing (2, 20, 40, 80) arranged therebetween, a drive shaft (4, 21, 48, 71) arranged in an interior space of the pump housing (2, 20, 40, 80) along a longitudinal direction, a conveying element (5, 22, 49, 73) arranged on the drive shaft (4, 21, 48, 71), wherein the conveying element (5, 22, 49, 73) comprises at least one flexible segment configured such that a direction of rotation of the conveying element (5, 22, 49, 73) causes a fluid to be conveyed from the distal end to the proximal end of the pump; and the pump housing (2, 20, 40, 80) is configured such that the pump housing (2, 20, 40, 80) is at least partially transferable into a cannula (3, 30, 47) under action of a force acting towards the proximal end of the pump, and is thereby transitioned from an expandable state into a compressed state at least along a radial direction extending transversely to the longitudinal direction; wherein an unfolding direction of the at least one flexible segment during a transitioning of the pump housing (2, 20, 40, 80) from the compressed to the expanded state is directed opposite to the direction of rotation, wherein the pump housing (2, 20, 40, 80) comprises a pump receiving portion (41; 85) and a proximal portion (44; 84) disposed proximally of the pump receiving portion, wherein an inner diameter of the proximal portion decreases from a diameter of the pump receiving portion in the expanded state of the pump housing (2, 20, 40, 80) towards a proximal end of the proximal portion, wherein the pump housing (2, 20, 40, 80) further comprises at least one portion which, in the expanded state, comprises structures (27; 46, 50; 82, 87) extending along the longitudinal axis spirally about the longitudinal axis, the structures being wound in a first direction as viewed from the proximal to the distal end of the pump, wherein the spiral structures (27; 46, 50; 82, 87) comprise spiral struts, wherein the spiral struts are disposed in the proximal portion (44; 84). wherein the conveying element (5, 22, 49, 73) comprises at least one flexible segment configured such that a direction of rotation of the conveying element (5, 22, 49, 73) causes a fluid to be conveyed from the distal end to the proximal end of the pump; and the pump housing (2, 20, 40, 80) is configured such that the pump housing (2, 20, 40, 80) is at least partially transferable into a cannula (3, 30, 47) under action of a force acting towards the proximal end of the pump, and is thereby transitioned from an expandable state into a compressed state at least along a radial direction extending transversely to the longitudinal direction; wherein an unfolding direction of the at least one flexible segment during a transitioning of the pump housing (2, 20, 40, 80) from the compressed to the expanded state is directed opposite to the direction of rotation, wherein the pump housing (2, 20, 40, 80) comprises a pump receiving portion (41; 85) and a proximal portion (44; 84) disposed proximally of the pump receiving portion, wherein an inner diameter of the proximal portion decreases from a diameter of the pump receiving portion in the expanded state of the pump housing (2, 20, 40, 80) towards a proximal end of the proximal portion, wherein the pump housing (2, 20, 40, 80) further comprises at least one portion which, in the expanded state, comprises structures (27; 46, 50; 82, 87) extending along the longitudinal axis spirally about the longitudinal axis, the structures being wound in a first direction as viewed from the proximal to the distal end of the pump, wherein the spiral structures (27; 46, 50; 82, 87) comprise spiral struts, wherein the spiral struts are disposed in the proximal portion (44; 84).