Fish has been regarded as an auspicious thing since ancient times, because its "fish" and "surplus" are homophonic, as the saying goes. In geomantic omen, good geomantic omen is to store wind and gather gas to get water, which is the best. Gas is circulating all the time, and it is easy to be blown away by the wind, breaking the balance of circulation, but it will stop when it meets water, so water can stabilize the transportation and circulation of gas. Moreover, there are auspicious things in the water, which can adjust the priorities of qi transportation and circulation and maintain the aura of the land of feng shui. The so-called lucky thing here refers to koi fish and koi fish, also known as "lucky fish" in Feng Shui.