The effect of the new Nanodessert nutritional biological product (the Nn product) has been studied on the juvenile Danio rerio laboratory fish, which were used for detecting the stimulating properties of the Nn product on the two important biological functions: the erythropoiesis, and the regeneration of the lost organs. As a result of the morphological and fluorescent histochemical analysis, it has been found that the most intensive regeneration of the fin lobe occurs on day 8 of the experiment. At this time, the growth of the cut-off upper lobes of the caudal fins of the fish that receive the Nn product with the feed is by 42 % greater than that of the regenerate of the fish that do not receive the Nn product. The histochemical studies have shown that in the regenerating caudal fin blastemas under the influence of the substances contained in the Nn product, the amount of RNA also increases, which contributes to increasing the protein biosynthesis and accelerates the restoration of the lost parts of the organs. © 2020, Seventh Sense Research Group.