The invention relates to an assembly for processing fish, comprising a fish slaughtering device with a fish counting device, a first conveying device for transporting the stunned fish to a spiral tank device, said first conveying device having at least one first measuring device that is designed to detect a first mass throughput of the stunned fish and the spiral tank device, which comprises a receiving container that is designed to receive liquid, said receiving container being equipped with a rotatably mounted spiral conveyor worm which together with the receiving container forms a plurality of fish receiving chambers in order to convey fish present in the fish receiving chambers through the liquid, a second conveyor device that is arranged at the second end of the receiving container and is designed to transfer the fish to at least one fish processing machine arranged downstream of the spiral tank device, and a controller with an analysis unit that is designed to ascertain a respective prediction variable for at least one of the fish receiving chambers on the basis of the detected number of fish and the detected first mass throughput. The invention additionally relates to a method for processing fish.
