[Automated translation from Polish abstract (No English abstract was available.) This study was carried out on 2 species of cyprinids: carp (Cyprinus carpio L.) aged 4 and 10 days and grass carp (Ctenopharyngodon idella) aged 10 days. The carp were fed with the "Ewos" larvstart C-10 pellets, intended for cyprinids, and the grass carp with pellets intended for trout. The carp at the age of 4 days emptied more than 50% of the intestine length in 1 hour after the discontinuation of feeding. In older larvae (10 days) the process was slower: the intestine was emptied 50% between 3 and 5 hours. For the first 2 hours of emptying, the feed remained in the intestine. In the case of white grass, food was found to remain in the intestine for 10 hours after the cessation of feeding. This indicates a lack of intestinal transit. what were the reasons for the negligible increase in cyprinids fed with fodder intended for salmonids.