Humic preparations are used as microfertilisers in crop production and growth stimulants in animal husbandry, in aquaculture there is a positive effect of these compounds on individual objects of cultivation, but their use in fish farming has not yet been understudied. The purpose of the work was to present the results of an experiment to evaluate the effect of fodder additive humates on the growth rate and survival of different age groups of sterlet (Acipenser ruthenus L., 1758) and the conversion of fodder by fish in aquaculture. A series of experiments were conducted on feeding sterlet with fodder with the addition of sodium humate. The research was conducted in 2018, 2020 and 2021 in the production conditions of the cage fish farm located at the Kaniv reservoir. The effect of various concentrations of sodium humate fodder additive on yearling and two-year-old sterlet was evaluated. Sodium humate was applied to the fodder for the respective groups of sterlet by spraying its aqueous solution in defined proportions with subsequent drying. It was established that the addition of sodium humate to fish fodder at concentrations of 60, 100, 120 and 200 mg/kg of fodder did not significantly affect the growth rate of sterlet. Thus, the advantage of the experimental variants over the control for this indicator was insignificant, within 1.0-1.6%. No effect of sodium humate on the survival of sterlet juveniles reared in cages was established. Therewith, the conversion of fodder with the addition of humates by juvenile and two-year-old sterlet was better by 6.7-17.4%. According to the experimental results, the best result was obtained in the variant using fodder additive humates at a concentration of 200 mg/kg of fodder. Based on the results of the research, it was established that in aquaculture conditions it is advisable to use sodium humate as a fodder additive for yearlings and two-year-old sterlet, designed to increase fodder conversion
biologically active substances, fish farming, sturgeon, survival, growth rate, fodder conversion