* Plankton: Tiny animals and plants that drift in the water column.
* Small invertebrates: Such as copepods, larvae, and other small organisms.
Sea pens catch their prey using tentacles covered in nematocysts (stinging cells) which paralyze their victims. They then bring the food to their mouths located in the center of each polyp.
Interestingly, some sea pen species also obtain nutrients through symbiotic relationships with algae living within their tissues. These algae photosynthesize, providing the sea pen with energy.