摘要 : The study was conducted in two consecutive years in the Fisheries and Aquaculture Institute - Plovdiv. For the needs of ecologo- and bio-friendly fish farming, the impact of some factors on the growth of carp fish reared in polycu... 展开 The study was conducted in two consecutive years in the Fisheries and Aquaculture Institute - Plovdiv. For the needs of ecologo- and bio-friendly fish farming, the impact of some factors on the growth of carp fish reared in polyculture, based on a natural nutritive basis, have been investigated. Rearing in autochthonous polyculture led to satisfactorily fish growth. The polyculture structure is a significant source of common carp growth variation, as the impact decreases when taking into account intense vegetation in the pond, and increases when taking into account the size of the pond. Common carp had better growth in one-year polyculture. The polyculture structure had no impact on bighead carp growth. One-year old grass carp grew more intensivelycompared to two-year old grass carp. Fertilization is a significant source for growth variation, but the impact is specific for the different species. Positive effect of the factor is established only for bighead carp. Significant sources for growth variation in all studied species are pond size and macrophytes density level. 收起