The article compares the morphological structure of the skeletal and muscular systems of carp and catfish carcasses and discusses how this determines the acquisition of semi-finished products - culinary elements. The results of weight measurements of the elements obtained from the processing of catfish carcasses, such as gutted carcasses, headless carcasses, flap, trimmed fillets without skin are presented. The processing and measurements were carried out on 34 pieces of fish (weight 45 kg). The weight spread of individual fish in the study group from 630 g to 2160 g. Measurements were made with a division into three size groups of fish.