The fish tapeworm, scientifically known as Diphyllobothrium latum, is a parasitic flatworm that primarily infects humans through the consumption of undercooked or raw fish. This tapeworm can grow up to several meters in length and resides in the intestines, where it absorbs nutrients from the host's food. Infection with the fish tapeworm can lead to a condition called diphyllobothriasis, which may cause symptoms like abdominal discomfort, diarrhea, and weight loss. While many infected individuals may remain asymptomatic, proper cooking of fish can effectively prevent infection and ensure food safety.