The Fiji mermaid was a common feature of sideshows, which was presented as the mummified body of a creature that was supposedly half mammal and half fish, a version of traditional mermaid stories.
During the Renaissance and the Baroque eras, the remains of mermaids were a staple of cabinets of curiosities. However the exhibit which created the Fiji mermaid concept was popularized by circus great P.T. Barnum, but has since been copied many times in other attractions, including the collection of famed showman Robert Ripley. The original exhibit was shown around the United States, but was lost in the 1860s when Barnum's museum caught fire. The exhibit has since been acquired by Harvard University's Peabody Museum of Archaeology and Ethnology and is currently housed in the museum's attic storage area.
The Fiji mermaid came into Barnum's possession via his Boston counterpart Moses Kimball, who brought it down to Barnum in late spring of 1842. On June 18, Barnum and Kimball entered into a written agreement to exploit this "curiosity supposed to be a mermaid." Kimball would remain the creature's sole owner and Barnum would lease it for $12.50 a week. Barnum christened his artifact "The Feejee Mermaid". In Barnum's exhibit, the creature was allegedly caught in 1842 by a "Dr. J. Griffin." Griffin was actually Levi Lyman, one of Barnum's close associates.
Though many people believed Barnum's claim, the Fiji mermaid was actually the torso and head of a baby monkey sewn to the back half of a fish and covered in paper-mâché.