Solution:

It is found that the fish tank water should be treated in time when it turns green. Strengthening and perfecting the in-cylinder filtration system and improving the filter's function of treating fish tank pollutants can effectively destroy the nutrients needed by green algae and make it difficult for fish tank water to turn green.

Change the water in time and manually remove the green algae on the surface of aquatic plants and fish tanks. You can keep some fish that only eat green algae in the fish tank, such as ornamental shrimp, ornamental snails, golden hamsters and black flying foxes.

Reduce the feeding of fish, and prevent excessive fish food from rotting in water and becoming nutrients for the growth of green algae. Reduce the density of fish farming and reduce the oxygen consumption in the tank.

Shorten the sunshine time of the fish tank, and the growth rate and quantity of green algae will be greatly weakened as long as there is insufficient light.

Extended data:

The reason why there are green algae in the fish tank: sunlight is the most important factor for algae to grow for a long time. If fish is fed too much, it will rot and deteriorate, becoming a nutrient for the growth of green algae and polluting the water environment (the water source contains green algae).

Harm of green algae to fish: The existence of green algae not only looks unsightly, but also absorbs oxygen from water and releases carbon dioxide. That is to say, green algae and fish compete for oxygen, which seriously threatens the life of ornamental fish and destroys their living environment.