Coming in as the third most popular pet are freshwater fish. Popular throughout the world, the largest population of goldfish, guppies and other aquarium dwellers is the United States, which had 170 million fish hanging out in over 13 million houses, doctor???s offices and other locations in 2006. In the UK, 24 million fish were kept as pets that year.

Though less affectionate than their furry or feathered counterparts, fish hobbyists are very attached to their aquatic companions, enjoying them for their calm beauty rather than their quality as company.