No. Sea pens resemble a quill pen and that is how they got their common name. Most amazing is that when brought to the surface the plume will light up green – glowing the entire sea pen! This is really the sea pen’s nervous system responding to predators.

Sea pens (just like their relatives the sea whips, sea feathers, and sea pansies) are cnidarians. This group is characterized by their specialized cells that are typically used for capturing prey.

Some of the specialized cells in sea pens are used to capture plankton for nutrients and others are used for transferring water in and out of its body. These types of specialized cells are the building blocks for the polyps that make up the colonies that then make up the long plumes of the sea pen.

Sea pens range in size from 4 inches to 6 feet. They are distributed worldwide in the temperate and tropical zones. There are 14 families within the order Pennatulacea.

Pictured is an orange sea pen.

Image (c) wierdseamonster.com.