The feeding experiment described was run within July 19 October 18, 1999 on 536 g (ą20 g) mean individual weight carp individuals aged 1+. The fish were kept in cages stocked at a 50 ind. cage1 density. Experimental treatments differed in the feed offered. The following feeds were used: Danex 1848 (Dan), Carp Growex (Grow), and AT 35 Starter (AT 35). The daily feed doses, amounting to 2.0% metabolic fish weight (W0.8) in each experimental treatment, were applied manually. During the first phase of the experiment (19 July 13 September), the metabolic growth rate (MGR) values were 17.40; 15.73; and 13.19 g kg0.8 in the Dan, Grow, and AT 35 treatments, respectively, the respective food conversion ration (FCR) being 1.15; 1.27; and 1.52. During the second phase of the experiment (14 September 18 October), the respective MGR values amounted to 15.17; 15.77; and 13.24 g kg0.8, while the corresponding FCR values were 1.32; 1.27; and 1.51.