Second, the quality of ink is related to dissolved oxygen, pH value and trace elements in water: generally, in the process of koi fish culture, the more dissolved oxygen, the lowest concentration of nitric acid in neutral and slightly alkaline water, which is quite beneficial to the development of ink quality in koi fish. If you can change the water regularly and supplement the trace elements in the water, you will not have stress or allergic reaction to the fish. You can also put some sand filter materials to supplement the slowly soluble silicon, and control the water quality at a lower hardness level (below 8 dh), so that the ink in koi fish will be black and shiny. In fact, in our real life, koi fish raised in new cement pools or underground wells and surface mountain springs has better ink quality for koi fish.
Third, the relationship between feed and the quality of koi fish ink: Minimizing the feed containing fat can enhance the quality of ink.
Fourth, the relationship between sunshine and koi fish ink: Although koi fish needs sunshine, it doesn't need direct sunlight on the surface of fish. Minimizing direct sunlight in koi fish is also helpful to the development of ink in koi fish.