Koi is an ornamental fish. Many fish friends will keep them in places with weak illumination, such as living room. If koi is not exposed to sunlight for a long time, their body color will fade. At this time, it is necessary to place the fish tank in a place with sufficient light for illumination two to three days a week, and the illumination time should be guaranteed to be about five hours each time. It should be noted that the illumination intensity should not be too strong, and astigmatism can be illuminated.

The color of koi is fixed. If you want to increase the brightness of color, you need to use brightly colored feed. Koi can increase its color through metabolism after eating colorful feed. Bright-colored ingredients such as earthworms, red nematodes, carrots, green vegetable leaves and shrimps can be added to the feed fed to koi, and can be fed once a day.

When the dissolved oxygen in water is very high, the concentration of ammonia will decrease, and the body color of carp will condense in the surface layer. When dissolved oxygen decreases, ammonia will increase, PH value will decrease, and the red crimson of koi fish will become lighter. Therefore, adjusting PH value properly can make koi fish color. At this time, the PH value of the water for maintaining koi fish should be properly adjusted to between 7.0 and 7.2.

If you want koi fish to fade after color enhancement, you'd better change the fish tank background to dark color. Because koi will change its body color with the change of its surrounding environment, if the background color is too light, the fish's color will also become lighter, which is its self-protection mechanism.