Natural spawning in controlled tanks takes place at the same time as natural spawning in open waters. It starts from the beginning of March to the end of June. Spawning activity always occurs between 19.00 and 23.00 h on the first to the 8th day of the full moon. As the female approaches full maturity there is an increase in spawning play activity. The ripe male and female swim together often turning laterally when swimming and then spawn. The fertilized eggs then float at the surface while the unfertilized eggs sink to the bottom. The floating fertilized eggs are siphoned out of the tank and placed in hatching tanks. The unfertilized eggs and other dirt at the bottom of the tank are removed by siphoning.
After the fertilized eggs are scooped out, the spawning tanks should be cleaned and prepared for new spawning activity. It is also possible that spawners can be spawned on different days within a spawning period in each spawning tank.
