Pearlfish, formerly known as tilapia, has a temperature range of 15 to 35 °C. When the water temperature is below 15 °C, the tilapia is dormant. The highest critical temperature of tilapia is about 40~41°C, and the most suitable growth temperature is 28～32°C. Therefore, in winter in Nanjing, the pearl fish is only in Jingshan Lake of Pearl Spring (the pearl spring water is low hot spring water, constant temperature). Only grow and multiply. The pearl fish has a delicious meat flavor and a delicate meat. It contains a variety of unsaturated fatty acids and abundant protein. In Japan, this fish is called a "protein source that does not require protein."