Eisenia fetida

Eisenia fetida, known under various common names such as manure worm, redworm, brandling worm, panfish worm, trout worm, tiger worm, red wiggler worm, etc., is a species of earthworm adapted to decaying organic material. These worms thrive in rotting vegetation, compost, and manure. They are epigean, rarely found in soil. In this trait, they resemble Lumbricus rubellus.

The red wiggler is reddish-brown in color, has small rings around its body, and has a yellowish tail. Groups of bristles (called setae) on each segment of the worm move in and out to grip nearby surfaces as it stretches and contracts its muscles to push itself forward or backward.

E. fetida worms are native to Europe, but have been introduced (both intentionally and unintentionally) to every other continent except Antarctica.

E. fetida also possesses a unique natural defense system in its coelomic fluid; cells called coelomocytes secrete a protein called lysenin, which is a pore-forming toxin, which is able to permeabilize and lyse invading cells. It is best at targeting foreign cells whose membranes contain significant amounts of sphingomyelin. (Lysenin is also toxic to organisms lacking sphingomyelin in their cell walls, including Bacillus megaterium, though the pathway is not understood).