Meeresringelwurm. Nereis fucata lebt als Kommensale in Schneckengehäusen von Einsiedlerkrebsen. Hat der Krebs ein Beutestück ergriffen, kriecht der Wurm hervor und entreißt ihm Teile der Nahrung aus den Mundgliedmaßen.

Nereis fucata being commensal with hermit crabs participates when its host, Eupagurus bernhardus, is feeding. The polychaete annelid crawls forward from the upper whorls of the shell, within which it is living, and seizes its food from the crab's maxillipeds. Small food particles are swallowed, while the anterior part of the worm is outside the shell, but large items are dragged into the interior before they are devoured. When feeding Nereis fucata mostly moves along the right side of the crustacean. Some worms regularly get to the left side crawling over the carapace.