A rotor for a pump has a housing and a rotor, and has at least one blade. The rotor is able to be actuated to rotate about an axis of rotation in order to convey a fluid in the axial or radial direction, and the rotor is able to be deformed in the radial direction between a first, radially compressed state and a second, radially expanded state. At a maximum speed of rotation of the rotor at which the power of the pump is at a maximum, the blade is essentially radially oriented, and/or the rotor has its maximum diameter.