This sentence is not scientific in nature, but it makes some sense philosophically.
If the water is too clear, there will be no fish; if the water is too clear, there will be no fish; if the water is too clear, there will be no fish; if the people are too smart, there will be no fish. No more companions.
In a natural sense, besides fish, there are other living things in the water. Frogs, crabs, and aquatic plants are also living things, so it is not scientific to say this in a natural sense. If "fish" represents all living things in the water, then it can be said that this piece of water has no meaning of existence. "Water is the source of life." Even if there is no life, is this a piece of stagnant water? Just like if there are people, there will be a society. The more people there are, the more complex and cruel the society will be. But without people, who will a society, no matter how simple and just, serve?