The fertilization of carp ponds as an important intensification means has been utilized in Europe since the first half of the 19th century, but even in most intensive fertilization the concentration of nitrogen (N) hardly exceeds 2 mg/l and of phosphorus (P), 0.5 mg/l. Polycultural carp growing using intensive mineral fertilization (weekly and every 3 days) has been experimented in the Freshwater Fishery Research Station in Plovdiv in the 1971–1972 period. The greatest zooplankton and benthos biomass and the greatest fish growth per ha water area are obtained with 3-day mineral fertilization with ammonium nitrate, 708 kg/ha and superphosphate, 395 kg per hectar. The average monthly water temperature in the experimental ponds during the vegetation period (June–September) fluctuates between 21.5 and 24.7°C. The oxygen dissolved (O 2) during the day hours changes within the average of 4.9–7.6 ml/l and the aeration is normal for the carp ponds (4.0–8.1 mg O 2/l). The highest average seasonal zooplankton biomass in mixed fertilization (mineral and organic) is 2.437 g/m 3. The zooplankton is represented by the following variaties: Rotatoria — Brachionus calyciflorus; Copepoda — Acanthocyclops vernalis and Cladocera — Moina rectirostric. The benthos consists of: chironomid larvae (family Chironomidae, Diptera) and Oligochaetae. The highest average seasonal biomass of the benthos is established with three-day mineral fertilization, 1.472 g/m 2. The total fish growth with three-day fertilization is 300 kg/ha higher than in the control ponds (without fertilization). The best fishery results have been achieved with three-day fertilization giving a total growth of the fish of 2 730 kg/ha and a food coefficient of 2.8.