The pump has inlet and outlet channels for receiving and outputting fluid, where volume fillable in a fluid space (55) is changed by controllable volume change of an element of a conveying device. The conveying device includes a blocking element (5) that is controlled with respect to the volume, where the blocking element completely releases the inlet channel and the outlet channel of the fluid space with an adjusted volume and completely blocks the channels with another adjusted volume. An independent claim is also included for a method for operating a fluid pump.
