The reasons why Luohan fish is not red:

1. Gene. The genes in the Luohan fish determine the expression of their skin color. If the red gene is not expressed in the Luohan fish, the skin color of the Luohan fish will not appear red.

2. Environment. The Luohan fish may not appear red when it is first bought home because it cannot adapt to the environment or is frightened.

3. Disease. Sick Luohan fish will show signs of body color, becoming darker or lighter.

Methods to make Luohan fish appear red:

1. If genes cause the skin color to not appear red, you can feed more feed containing astaxanthin and it will improve. , you can also put up red wallpaper or turn on red lights, which can not only improve the skin color of Luohan fish, but also play a decorative role.

2. The Luohan fish you just bought home needs to stop eating for two days, do not turn on the lights, and do not scare the small fish. After a few days, the Luohan fish will gradually adapt to the environment and its body color will recover.

3. If the red color cannot appear due to disease, the water temperature should be raised to 32 degrees first, and coarse salt used for fish should be sprinkled to alleviate the condition of the Luohan fish. And use medicine to target the diseases of Luohan fish. After the disease of Luohan fish is cured, it needs to rest for another 3 days. After the condition is completely restored, the body color will gradually return.