Koi fish start to change their colors when they are half a month old. Usually, at the age of half a month, the colors of koi fish begin to fade and gradually become clearer, and their patterns will also gradually emerge.
The color change process of koi fish can be divided into the following stages:
At half a month old: The color starts to fade, and the pattern begins to appear.
At the age of 1 year: The color and pattern develop further, and the skin and texture become more distinct.
At the age of 2 years: The color and pattern change further, and some koi fish will experience a magnificent transformation.
Between the ages of 3 and 4: The color and pattern are basically fixed, and the quality becomes more definite.
In addition, the color change of koi fish is also affected by the water quality and the environmental temperature. Changes in the water quality environment can cause a white film to appear on the surface of koi fish.