Why are there ponds in front of villages in the Pearl River Delta? What is the function of the pond?

Fish farming, big brother . . . If it's related to Feng Shui, it's because all sects have always agreed that it's better to surround water with winding water. Since the mountains are hard to change and the "water" on the road is hard to change, we have to change the water in front of the village entrance, so we artificially dug some fish ponds to let the village entrance suck more water-water is wealth; It's just that the orientation and distribution of fish ponds in the village are mostly problematic, which leads to the activities of the white tiger, or the white tiger has poisonous water and stagnant water, which is another matter.