A wonderful and short history of the humble goldfish presented by National Geographic. 
 
"Oh, wet pet," American poet Ogden Nash wrote in pithy summation of the humble goldfish, whose habitat is, by tradition, a glass bowl anchored by the faux luxury of a gravel-bound ceramic castle. But the reality is more complex, suggests a new book by Anna Marie Roos, a professor of the history of science and medicine at the University of Lincoln, in England.
 
The epic history of goldfish—pet and pest (nationalgeographic.com)