Atractolytocestus huronensis is a tapeworm parasite of Cyprinus carpio (Common Carp), native to East Asia, and introduced to North America in the 19th century. The parasite was described from the Huron River, near Ann Arbor Michigan (Anthony 1958). The parasite has been collected from C. carpio in the Tennessee River, from Wisconsin and Arizona. The parasite is also spreading among wild and cultured C. carpio in Europe and South Africa. Genetic studies confirm its origin in Asia. In 1966-67 this parasite was collected in C. carpio in a survey of fishes of the Tracy Pumping Plant in the Sacramento-San Joaquin Delta. In cultured carp, this parasite causes minor intestinal damage, but does not affect growth or survival of the ifsh.