A pump, in particular a blood pump , with a proximal and a distal end and a pump housing arranged therebetween, a drive shaft arranged in an interior space of the pump housing along a longitudinal direction, a conveying element arranged on the drive shaft , wherein the conveying element comprises at least one flexible segment configured such that a direction of rotation of the conveying element causes a fluid to be conveyed from the distal end to the proximal end of the pump; and the pump housing is configured such that the pump housing is at least partially transferable into a cannula 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 from the compressed to the expanded state is directed opposite to the direction of rotation, wherein the pump housing 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 towards a proximal end of the proximal portion, wherein the pump housing 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 comprises at least one flexible segment configured such that a direction of rotation of the conveying element causes a fluid to be conveyed from the distal end to the proximal end of the pump; and the pump housing is configured such that the pump housing is at least partially transferable into a cannula 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 from the compressed to the expanded state is directed opposite to the direction of rotation, wherein the pump housing 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 towards a proximal end of the proximal portion, wherein the pump housing 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). <EOS>