Nassarius fraterculus

Nassarius fraterculus is a species of sea snail, a marine gastropod mollusk in the family Nassariidae, the Nassa mud snails or dog whelks. The shell grows to a length of 10 mm. This marine species occurs off China, Korea and Japan, but has been introduced to the Pacific Northwest of North America through commercial oyster shipments.

Habitat
N. fraterculus inhabits intertidal regions, foraging on crushed mussels.

Relationship to other invasive species
In the Pacific Northwest, N. fraterculus has been shown to benefit from the presence of Batillaria attramentaria, another invasive species.