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What are Sea Pansies?

A. B. Kelsey
A. B. Kelsey

Sea pansies are fleshy, leaf-shaped colonies of marine organisms that belong to the genus Renilla, which is in the same Cnidaria phylum as jellyfish and corals. In fact, they are not a flower, but are actually a type of soft coral known as Pennatulacea. They are considered aggregate organisms, which is a colony made up of numerous individuals.

Colonies of sea pansies consist of stalks formed by large organisms called primary polyps, which can be up to 2 inches (5.08 cm) in diameter. These primary polyps have a fleshy structure called a peduncle that extends from the bottom of the main colony. The peduncle thrusts itself in the sand to anchor the pansies to the ocean floor.

Sea pansies may be found in the warmer areas of the Pacific and Atlantic coasts.
Sea pansies may be found in the warmer areas of the Pacific and Atlantic coasts.

The pansy-like body that gives the sea pansies their name is actually made up of various types of smaller, secondary polyps. Some of these secondary polyps are responsible for feeding the pansy. These feeding polyps extend above the sand and secrete sticky mucus to snare any tiny zooplankton and organic matter that venture nearby. Each feeding polyp sends its food to a common digestive system so the entire colony feasts or starves together.

Sea pansies are a type of coral.
Sea pansies are a type of coral.

Small white dots are located in between the feeding polyps. These light specks are a specialized polyp that acts as a kind of water pump or outlet valve that deflates and inflates the entire colony. This comes in handy when the sea pansy is threatened by a predator or gets stuck on a sand bar at low tide.

Sea pansies have stalks that are red, blue or purple and studded with brilliant white polyps. Sea pansies are strikingly bioluminescent when they are touched or attacked by a predator. This bioluminescence is caused by Green Fluorescent Protein (GFP). This protein generates bright green waves of light that pulse outward from the point of contact. These pulses of light often help to distract the potential predator.

These unusual creatures are typically found in the warmer areas of the Pacific and Atlantic coasts and are sometimes referred to as "Atlantic coral." These organisms begin begin life as planktonic larvae that all hatch from the same egg. All of the polyps are clones of one another. As the sea pansy matures, it moves in towards shallower sand flats using contractions of the entire colony. These organisms love to anchor down in sand flats and are often found living completely buried in the sand.

Frequently Asked Questions

What exactly are sea pansies?

Sea pansies are marine invertebrates belonging to the group of animals known as cnidarians, which also includes jellyfish and corals. They are a type of soft coral scientifically referred to as Renilla reniformis. These organisms are notable for their vibrant colors and their flat, oval shape that resembles a blooming flower, hence the name "pansy."

Where can sea pansies be found?

Sea pansies are typically found in the sandy or muddy bottoms of warm, shallow coastal waters, particularly in the Atlantic Ocean along the eastern coast of the United States. They thrive in environments where they can anchor themselves to the substrate using a specialized structure called a peduncle.

How do sea pansies feed?

Sea pansies are filter feeders that capture plankton and small particles of organic matter from the water column. They use their feathery tentacles, which are equipped with stinging cells called nematocysts, to ensnare their prey. The tentacles then transport the food to the central mouth for digestion.

Do sea pansies exhibit any unique behaviors?

One of the most fascinating behaviors of sea pansies is their bioluminescence. When disturbed, they can emit a soft, greenish-blue light due to the presence of luciferin and luciferase enzymes. This light display is thought to startle predators or may play a role in communication between individuals.

Are sea pansies important to their ecosystem?

Sea pansies play a crucial role in their ecosystem by contributing to the biodiversity of the ocean floor. They provide habitat and feeding grounds for various small marine creatures. Additionally, as filter feeders, they help maintain water quality by removing suspended particles from the water.

Can sea pansies be kept in home aquariums?

Keeping sea pansies in home aquariums is possible but can be challenging due to their specific care requirements. They need a stable environment with proper water flow, lighting, and a supply of fine particulate food. Only experienced aquarists should attempt to maintain these delicate organisms to ensure their health and well-being.

Discussion Comments


Sea pansies are beautiful, but I am intrigued by the look of sea pens. They look just like the quill pens used long ago. When attached to the sea floor, they look like they have been jabbed into the sand as though it were an inkwell!

Like the sea pansy, the sea pen is made up of a colony of polyps. They work together to survive, sharing food. It’s neat how they give up their individual identities. The primary polyp actually sacrifices its tentacles to become the pen’s stalk. The stalk has a bulb at the base that anchors the whole sea pen to the sandy bottom of the sea.


I owned a sea anemone once, and you have to be really careful with them to keep them alive. Sea anemones, a relative of sea pansies, often die quickly when handled. It is easy to accidentally tear the body, usually when trying to separate the foot from whatever it has attached to, whether in the wild or in an aquarium. You must patiently remove it by carefully and slowly sliding a nail under it and around the whole area that is attached. Then, you should bag it underwater.

Sea anemones can be hazardous to humans. Don’t let their slime or their bodies touch your eyes, skin, nose, or eyes. Though most people can handle short-term contact, you never know if you will be one of those who is sensitive to the creature. Wear rubber gloves if you must touch the anemone.


@anon165712 - If you live in or visit northeast Florida, you might find one washed up on the beach. I live in that area, and I have seen several. Often, rough surf conditions and northeasterly winds wash up sea pansies, which then live buried totally in the sand.


Wow, I hope these siblings don't mind sharing! Imagine having that many brothers and sisters and having to all eat literally the same food!


where can i get one?

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    • Sea pansies may be found in the warmer areas of the Pacific and Atlantic coasts.
      By: Netwalker
      Sea pansies may be found in the warmer areas of the Pacific and Atlantic coasts.
    • Sea pansies are a type of coral.
      Sea pansies are a type of coral.