Why do most people keep tropical fish now and few people keep goldfish?

Playing goldfish is mainly in old Beijing, and there is no old tradition left by tropical fish. Playing goldfish is a kind of kung fu and a tradition. Tropical fish are colorful and beautiful. The disadvantage is that it needs heating and electricity in winter. The key is to see what fish you like. Nowadays, many young people like to keep tropical fish. Tropical fish species are richer in color and more beautiful. But it needs to be heated to more than 20 degrees to survive. Especially in winter, it takes a lot of electricity. I am a child who grew up in an old Beijing hutong, and I grew up with the little goldfish. In the past, the conditions in the hutongs were very poor, the bungalows were very cold, and everyone burned coal. Who has money to heat the fish? But goldfish don't need it. As long as there is running water, adding some oxygen will give you vitality. Living in a building now makes life better. But I still like keeping goldfish. A cup of tea, a square jar, a group of well-kept goldfish, a water pump and some fish food are the simplest and happiest. No matter what others think, I will always love the goldfish in old Beijing.