Only certain aquariums are home to whales. For example, there are killer whales and flower whales in the polar ocean world of Hefei Hanhai, and there are large white whales in the Beijing Aquarium.
Whales belong to the phylum Chordata, the subphylum Vertebrates, the class Mammalia and the subclass Eutheria. They include approximately 98 species of viviparous mammals that live in oceans and rivers. There are more than 30 species in Chinese waters. All cetacean species inhabit the ocean, with the exception of a few species that live in fresh water. The smallest known species currently exceeds 6 meters in length, and the largest animal in the world, the blue whale, is also a baleen whale. However, the body shape of toothed whales varies greatly. The smallest species is only about 30 cm long and the largest sperm whale is over 20 meters long. Whales are notnot fish. Whales belong to the class of mammals.