shuǐ zhì qīng zé wú yú 水至清则无鱼
No Fish Survive If Water Is Too Clear.
Fish cannot survive in the water that is too clear. With no plankton in water, fish have nothing to feed on and are bound to die. This is a natural phenomenon. Drawing inspiration on it, ancient Chinese believed that one should not set the bar too high for a person or something, criticize a person for failing to be perfect, or be too strict with others. Instead, they held that one should be tolerant and inclusive. This term echoes the thinking of “having great virtue and accommodating all things.”
Fish cannot survive in the water that is too clear. One will have no friends if he is too shrewd. (The History of the Han Dynasty)