Written by the Fiveable Content Team โข Last updated August 2025
Verified for the 2026 exam
Verified for the 2026 examโขWritten by the Fiveable Content Team โข Last updated August 2025
Definition
Shellfish is a broad term used to describe aquatic animals with shells such as clams, mussels, oysters, shrimp, lobsters, and crabs. They play important ecological roles while also being a popular food source for humans.
Mollusks: Shellfish are part of the larger group of mollusks, which also includes snails and squids.
Crustaceans: Crustaceans are a subcategory of shellfish that have jointed appendages, exoskeletons, and two pairs of antennae. Examples include crabs and lobsters.
Filter Feeders: Many shellfish species are filter feeders, meaning they extract nutrients by filtering water through specialized structures like gills or siphons.