Triaenophorus nodulosus, the pike tapeworm, is a species of parasitic cestode (tapeworm) in the family Triaenophoridae. It is known to infect the northern pike, as well as other piscivorous fish, being found in the intestine of its host. It has been found in North America, Europe and England.
Adult specimens of Triaenophorus nodulosus have been seen to range from long. When having a developed egg in the uterus, their maximum width is . There are four hooks on the scolex, with an angled plate about wide and deep. Its cirrus sac is long.
The eggs of the species are white, but turn brown around 45 minutes after being placed in water. They are ovoid; they are about long and in diameter. Oncospheres can be made out inside ripe eggs. Coracidia are around the same size of the egg, and are ovoid as well. They are about long and wide.
Triaenophorus nodulosus has been found in a variety of fish, such as the northern pike, the coho salmon, the sockeye salmon, the Great Lakes muskellunge, and the walleye, as well as other fish from the United States and Canada. It uses piscivorous fish as definitive hosts, and uses smaller, preyed-upon fish or other marine organisms, such as copepods in the genus Cyclops, as intermediate hosts. When infecting its hosts, it embeds itself in the intestines or viscera.