Common fish are either edible fish or ornamental fish. Edible fish mainly include carp, crucian carp, grass carp, bream, tilapia and perch. Ornamental fish include goldfish, koi fish, arowana, arhat, map fish, peacock fish, lamplight fish and parrot fish. Some belong to tropical fish, so we should pay attention to heat preservation when raising them. Some big fish need to be oxygenated with oxygen-increasing equipment because of their high oxygen consumption.