If there is too much moss in koi fish pond, it is best to salvage it manually. This moss is an aquatic plant, which can be used as food for fish, but too much moss will also affect the light and reduce the dissolved oxygen in water, so it is best to clean it up. In addition to manual fishing, you can also raise some herbivorous fish to clean up, or prepare some algae removers, but the dosage must be controlled, otherwise it may cause certain phytotoxicity to fish.

1. Water is too fat: The reason for growing moss is that the water in the fish pond is too nutritious, that is, the water is too fat. It should be noted that in the process of mass reproduction of moss, it will also absorb the nutrition of water body, thus making the water thin, which will be unfavorable to the growth of fish. Therefore, it is necessary to properly fertilize and supplement after cleaning moss.

2. Sufficient illumination: As a kind of plant, moss can't grow without illumination. If the illumination is too sufficient, it will cause it to multiply in large numbers. However, if it is properly shaded, it will stop growing due to lack of light and other reasons. It is worth mentioning that if the light is too scarce, the growth of fish will also be affected.

3. Lack of aquatic plants: If there are aquatic plants in the fish pond, the growth of moss will also be limited. Both aquatic plants and moss need nutrients in water, so they will form a competitive relationship. Therefore, as long as aquatic plants are planted well, moss will disappear slowly.