1. Because it requires high water quality, if the water quality deteriorates or the water temperature fluctuates too much, the crested medaka may get sick or die.
2. In addition, if the number of aquaculture is too large, it is difficult to ensure that the water quality of each aquarium is kept good, which may cause the fish in the whole aquarium to be affected. In addition, if medaka are kept as pets, they may have a negative impact on the ecological environment.