In the paper, the technical aspects of modeling the retention system of matrixtype cages for industrial fish farming in a pond is considered. To date, there is no developed calculation methodology that takes into account the layout features of each cage module. The layout of the modules can vary significantly: from 1 to 36 cages of various designs. The aim of the work is to substantiate the parameters of the holding ropes, the length of the pull chains and the required mass of anchors by calculating the tensile forces in the ropes and the reaction of the anchor supports when solving the dynamic task in an unsteady setting. To solve this problem, a dynamic system was developed considering wind, wave, and inertial loads acting on all elements of the system: cage, holding ropes, chains, anchors. The force acting on the surface of the cage from the wind is received. The values of tensile forces in the ropes, the reaction of the supports of the anchors in three planes are obtained. The lengths of the chains are identified, ensuring the absence of tearing forces acting on the anchors. The masses of anchors are calculated taking into account the Archimedean force, depending on the density of the anchors’ material. The simulation lasted for 60 s. At 37 seconds of calculation, a resonant phenomenon was revealed: a significant increase in the breaking strength in the rope.