Abstract: The invention relates to a fluid pump, in particular liquid pump, with a rotor, with a rotor shaft (11) and with at least one rotor blade for delivering the fluid, wherein the rotor with regard to its diameter may be changed between a first, compressed condition, and a second expanded condition, wherein the at least one rotor blade comprises at least two erection elements (12, 13, 14) which are distanced to one another along the longitudinal axis (18) of the rotor shaft (11) and which project away from the shaft in the expanded condition of the rotor, as well as at least two limp rib elements (25, 26, 27, 28, 29, 30) which run at a distance to one another from one erection element (12, 13, 14) at least up to a further erection element, wherein a limp membrane (10) is held between the rib elements, which is tautened in the expanded condition of the rotor.