|"'Feejee Mermaid' has become the generic term for the many fake mermaids that can be found around the world..."
This article contains information relating to a hoax. According to Cambridge dictionary a hoax is "a plan to deceive a large group of people; a trick."
Fur-Bearing Trout (also known as Beaver Trout or 'Furry Fish') possess thick coats of fur or hair that help to keep them warm in the cold northern waters where they are said to have lived.
According to legend, the fur-bearing trout was first encountered by Europeans when Scottish settlers emigrated to Canada during the seventeenth century. One settler wrote home remarking about the abundance of "furred animals and fish" in the new land. Asked to provide more information about the furried fish, he duly sent home a specimen. Fur-Bearing trouts mounted as trophies can be found hanging on walls throughout the Great Lakes region of North America.
The legend probably started by people seeing trouts infected with saprolegnia, which makes the fish seem to have tufts of fur. It is also possible that a taxidermist put fur on a trout and showed it around and convinced some people.
Beaver Trouts mounted on walls are all considered hoaxes. Also you can see how the skin is made of plastic when they are on the wall.