Scientists have discovered the first known transmissible cancer in fish, the 4th naturally occurring cancer known to spread between animals Anglers noticed the disease in 2012 in bullhead catfish in a Vermont-Québec lake. Thoreau might even have seen it in the 1850s. www.nature.com/articles/d41...
Rare contagious cancer discovered in wild catfish
Transmissible tumours have been found in only a few types of animal, but there might be many more out there.
nature.com