Related Program: Word of Mouth Goldfish Invaders By Virginia Prescott • Nov 8, 2012 Related Program: Word of Mouth TweetShareGoogle+Email Credit piddy77 via Flickr Creative Commons Listen Listening... / 6:50 A 2004 poll estimated that thirteen percent of American households keep goldfish. Nearly 500 million are sold each year just to feed other pets. How goldfish became America’s go-to pet is a matter of some debate. Katrina Gulliver is a historian and freelance writer who wrote "The Great Goldfish Invasion" for The Atlantic magazine that traces the origins of this disposable aquatic pet. Tags: Environmentpop cultureTweetShareGoogle+EmailView the discussion thread.