1. The peacock fish suffers from diseases, such as white spot disease and water mold, which will affect its color.

Second: the water quality is not suitable. Only when the guppy lives in a suitable water environment will it grow and develop normally and its body color will be bright. If the water quality is turbid for a long time, the residual bait and feces in the fish tank are not cleaned in time, which will inevitably affect the tail color of guppy and even induce some diseases.

Third, the nutrition is not balanced: The nutrition absorption of the bait is also very important if the guppy tail wants to have a good performance. If the nutrition of the bait can't keep up, then the peacock fish will naturally not perform well, and the body color of the peacock fish will not be very bright. Of course, the color of guppy's big tail will fade.

Fourth: the fish are old and weak, and the guppies are artificially raised. Life expectancy is about 2 to 3 years in good environment. The color of the old fish will gradually fade.

According to your photos, it shouldn't be the water quality, and you can't see the characteristics of the disease. In most cases, the fish may be frightened or old. For reference only.