Abstract: A pump for conveying a fluid comprises a pump housing (1) with a fluid inlet (26), a pumping chamber (4), which has a flow connection to the fluid inlet (26), and a fluid outlet (25), which has a flow connection to the pumping chamber (4). The pump furthermore has a drivable pump body (2), which at least partially limits the pumping chamber (4), and a pump body drive device. The pump body drive device comprises a pump body drive mechanism (3) which is connected to the pump body (2) and which comprises a first drive magnet (16) and is moveable along a displacement path, and a second drive magnet (11) arranged adjacent to the pump body drive mechanism (3) for moving the pump body drive mechanism (3) along the displacement path. The pump also comprises an actuable fixing device (33) for fixing the pump body drive mechanism (3), which, in a release position, releases the pump body drive mechanism (3) and, in a fixing position, fixes the pump body drive mechanism (3).