A apparatus for detecting cells or particles in a fluid container includes a dispenser configured to dispense at least one cell or at least one particle into a defined sub-volume of a fluid with which the fluid container is at least partially filled, and a detection apparatus configured to, in a time-coordinated manner with dispensing the at least one cell or the at least one particle by the dispenser, perform a detection in the defined sub-volume and/or in one or several sub-volumes underneath the defined sub-volume in order to sense the at least one cell or the at least one particle when entering the fluid or immediately after entering the fluid.