In reality, a possible source may have been a simple misunderstanding. A 17th century Scottish immigrant's letter to his relatives referring "furried animals and fish" being plentiful in the New World, followed by a request to procure a specimen of these "furried fish" to which the mischievous Scotsman readily complied by making one up, is often cited. In fact, the "cotton mold" Saprolegnia will sometimes infect fish, causing tufts of fur-like growth to appear on the body. A heavy infection will result in the death of the fish, and as the fungus continues to grow afterwards, dead fish that are largely covered in the white "fur" can occasionally be found washed ashore.
The hoax can be unequivocally documented to go back to at least the 1930s. For example, here's an excerpt from an article in the Pueblo Chieftain dating back to November 15, 1938:
Stuffed and mounted specimens of these fish can be found in a number of museums of curiosities. These are made-up; the Saprolegnia "fur" cannot be preserved by taxidermy, and heavily overgrown fish are usually found only after they have already started to decay.
The fur-bearing trout and people's gullible reaction to it was part of a scene in the French movie Brotherhood of the Wolf. The Fur Bearing Trout also appeared in 2 episodes of the Earthworm Jim TV Series in an episode where Jim went on a roadtrip to find it and save it from Queen Slug-for-a-Butt and another episode where Jim had to stop the anti-fish from eating the great worm spirit.
HARVEST TIME SERVES UP ITS BOUNTY, ITS COLORS FUR-BEARING ANIMALS FATTEN UP, WHILE BIRDS GET READY TO HEAD SOUTH.(Local/ Wisconsin)
Oct 01, 2000; Anita Treinen drove a front-loader in from her pumpkin patch with 50 pumpkins to add to the 960 or so orange spheres already...