The carp (Cyprinus carpio) rearing in polyculture with grass carp (Ctenopharyngodon idella) - a condition for farming efficiency.

The study aimed to use the natural trophic capacity of fish ponds using different Cyprinids species. Biological material consisted of 3 groups of Cyprinus carpio and Ctenopharyngodon idella. The achieved results showed that the groups fed differently obtained also different growth performances. The best results were obtained when the Cyprinus carpio was fed with concentrate feed, the consumption was 9.6 g/ capita. Ctenopharyngodon idella preferred the reed instead of mowing clover, the consumption was 109.1 g/ capita. The fish fed with combined feed realised the best results regarding fattening level (4.8 points) and those fed with mowing clover administered to the pond obtained 3.6 points. The Ctenopharyngodon idella realised a fattening level of 4.2 points. It may be concluded that the two species can be reared in polyculture succeeding to exploit the aquatic vegetation from the pools where the vegetation exists.