Abstract: An apparatus and method for ventral/dorsal alignment of fish with a first fish conveying device, a guide roller for transversely positioning the fish in a feed-in channel, the guide roller extending across the width of the feed-in channel and having at least one section with reduced cross-sectional diameter, a channel floor in the centre of the channel comprising a transfer recess, widening in the conveying direction, to transfer the fish by effect of-gravity to a guiding channel arranged below the first conveying plane by aligning in a predetermined ventral/dorsal position, the guiding channel comprising lateral guide surfaces each arranged inclined with respect to the first conveying plane, and a second conveying device, forming a second conveying plane and configured to convey the fish on their side, said second conveying device being arranged downstream of the guiding channel for taking over the fish at the end of said guiding channel.