Abstract: A device for positioning of fish into their correct position for decapitating is disclosed. This device is applicable in fish-processing machines in which the fish lying transverse to their longitudinal extension in receiving troughs of a chain of troughs are fed to a decapitating tool. To this end, a shifting device comprises a shifting element engaging the snout of the fish and being activated and positioned dependent on the detection of the thickness of the fish in the region of its head. A feeler is coupled to a position sensor which emits measuring signals dependent on the position via a control circuit to control a stepping motor which drives the shifting element.