In ancient times, it was very important to have a pool in a big house of a big family. Water was synonymous with wealth in ancient times because of aquatic money. There is a pool in the yard. There is water in the pool. Some water is naturally fish.
There are fish surplus every day and fish surplus every year, which is the embodiment of wealth accumulation and glory. So let's narrow it down to fish in the water first. Among the fish, koi fish is a symbol of good luck, which is called good luck fish and feng shui fish.