The nutrient-rich water in the fish pond needs to be changed regularly.
Tips
usage
The proverb 肥水不流外人田 (don't let rich water run into outsiders' fields) is by far the most common context — used to justify keeping money, jobs, or opportunities within one's own family or circle.
history
肥水 also names a river in Anhui where the 383 CE 淝水之战 (Battle of Fei River) was fought; the former Qin army was routed by Eastern Jin, an upset that gave rise to the chengyu 草木皆兵.
