Adults live in the intestine of freshwater fish of the genus Esox. They mature in synchrony and detach from the intestine when the host is spawning in shallow water. The eggs develop in a few days and release a coracidium that swims to maintain a position in the water column. Copepods eat the coracidium and the enclosed embryo penetrates the stomach and moves into the hemocoele. In a few weeks it has developed into a procercoid larva that is infective to second intermediate host fish. When eaten, the procercoid migrates through the gut wall, across the body cavity, and into the tissues. The parasite begins a several-month-long process of developing into a plerocercoid. During that time it meanders through the tissues, usually the body musculature but occasionally to aberrant sites such as the brain. When development is complete, the plerocercoid stops migrating and the host deposits a connective tissue capsule around the parasite. The plerocercoid can survive within this capsule for more than one year. When eaten by a definitive host, the plerocercoid attaches to the intestinal wall and begins growing.