Geoducks are filter feeders, meaning they eat by filtering tiny organisms out of the water. They primarily feed on:

* Plankton: These are microscopic organisms that drift in the water, including phytoplankton (algae) and zooplankton (tiny animals).

* Sediment: Geoducks can also consume sediment, which contains organic matter and small organisms.

* Bacteria: Geoducks can filter bacteria out of the water column.

They use their siphons to draw water into their bodies and filter out the food particles.