List of diseases and parasites in cod

The first host used by cod worm is a flatfish or lumpsucker, which it captures with grasping hooks at the front of its body.

There, the worm clings to the gills while it metamorphoses into a plump, sinusoidal, worm-like body, with a coiled mass of egg strings at the rear.

There, firmly rooted in the cod's circulatory system, the front part of the parasite develops like the branches of a tree, reaching into the main artery.

[1][2] Atlantic cod act as intermediate, paratenic, or definitive hosts to a large number of parasite species; 107 taxa are listed by Hemmingsen and MacKenzie (2001)[3] with seven new records by Perdiguero-Alonso et al.

"Composition and structure of the parasite faunas of cod, Gadus morhua L. (Teleostei: Gadidae), in the North East Atlantic".