Cooperative Fish and Wildlife Research Units Program: Arizona
Education, Research and Technical Assistance for Managing Our Natural Resources

Praziquantel, an anthelmintic, is commonly used to control Asian tapeworm Bothriocephalus acheilognathi in grass carp Ctenopharyngodon idella and baitfish during transport. It is also used for controlling Asian tapeworm in small ponds. We treated several cyprinid fishes, both native and non-native to Arizona, with praziquantel. At the recommended dosage, Praziquantel killed adult tapeworm, but some tapeworm ruptured and released eggs. Eggs released from Asian tapeworm treated with praziquantel were viable and produced coracidia over several days. Fishery managers should be aware that even if fish receive a typical praziquantel treatment regime and all adult tapeworms are killed, viable eggs and coracidia may be present in the holding water or attached to the skin of treated fish, surfaces of equipment, or to treatment personnel. The student graduated spring 2007, and this work was published in the North American Journal of Aquaculture in 2009.