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Project title or topic of activity

Clowning Around Sea Anemones

Author(s): Kim Kanuho

Date: Fall 1999


Summary of Activity
50-100 words

This activity should demonstrate the association created between the sea anemone and the clownfish. Most organisms that come into contact with the sea anemone are paralyzed by the stinging cells from the sea anemone's tentacles, then eaten. The clown fish is one organism that is able to live with in the sea anemone without being eaten or stung. How is this possible? It is called symbiosis, or the relationship between the two. Each contributes to the relationship in order to survive. The clownfish seeks protection and the sea anemone needs a lure for food.


Grade levels

the third grade.

General description or introduction
The scientific principles that the activity is founded on.

This activity is based on the scientific principle of symbiosis. Throughout the world organims maintain strange relationships, sometimes it is unknown why, but in this case the clownfish and sea anemone are frequently studied. Scientists have based their conclusions on observations and studies between the two.

Background information

Sea anemones are marine animals in the Cnidaria phylum. These sea creatures are often mistaken as marine plants or flowers. The body is composed of a columnar structure, with one end of the column attacked to a substrate, and the other end houses the mouth and tentacle structures or nematocysts, a type of cnidae. The cnidae or nematocysts contain stinging cells that paralyze the prey. Sea anemones do not actively seek food, instead they are opportunistic feeders, meaning they wait for passing prey.

They are found in coastal regions throughout the world, but mainly in warm temperate regions. The depth at which they are found varies, some sea anemones can be found in shallow parts of the ocean, while others occupy deep-sea waters. The home for sea anemones vary, some seek substrates that are sedentary - like rocks. While, others seek mobile substrates, such as a hermit crab shell. In coral reef areas, space is limited so some sea anemones compete for space. The anemones use their nematocysts as weapons.

The clownfish or damselfish is a fish found in warm waters, mostly in the coral reefs. The fish colored bright orange with white stripes. They are highly defensive of their territory, but are often mistaken as "clowning around," hence the name. Clownfish are small and are easily sought as prey. To avoid predation, the fish seek refuge among tentacles of sea anemones.

The relationship between the Clownfish and sea anemones is called symbiosis. In Greek, symbiosis means 'life together', where two organisms maintain a relationship with each other in order to survive. The association can be described as mutualistic, in that they both benefit from living together. The Clownfish seeks protection among the tentacles of the sea anemone, and the sea anemone obtains food by capturing the clownfishes' predator.

In order for the Clownfish to live within the tentacles of the sea anemone, it must develop immunity to the stinging cells of the anemone. It does this by touching one or two tentacles at a time, over time the number of tentacles touched are numerous and eventually the fish creates mucus that protects it from the sting cells of that specific sea anemone. Once the clownfish does create a relationship with an anemone, it must stay with that specific anemone, because the stinging cells of individual sea anemones are different.

Studies have showed that the clownfish are initially attracted to the chemical secretions of the sea anemone. And eventually it is able to recognize the sea anemone visually. Clownfishes do not usually venture far from the sea anemone, because it must rely on it for protection. Studies have found that the clownfishes do not survive for long if they leave the vicinity of its specific sea anemone.

Credit for the activity

This is an original idea.

Estimated time to do the activity

The activity should last about 10 minutes.

Goals of Activity:

Goal A
Identify regions where the sea anemone and clownfishes can be found.

Goal B
Describe the relationship between sea anemones and clownfishes.

Goal C
{Goal C}

Goal D
{Goal D}


National Science Education Standards. (NSES)

Two content standards that this lesson plan covers:

Standard 1
Organisms and their environments.
The focus is on establishing a primary association of organisms. Their dependence on the environment and behaviors, and defining the behaviors that help them survive within that environment.

Standard 2


Materials Needed

  • World map,
  • pictures of sea anemones and clownfishes,
  • desks or table tops,
  • 1 plate of cookies per group.


Give back ground lecture. Defining terms and showing pictures of the sea anmone and the clownfish.

Step-by-Step Procedure for the Activity

This is a group activity that will involve the whole class.

This is a group activity. Depending on the size of the class, divide class into 3 groups. Have 1 group of students be the clownfishes, one group to act as predators, the rest will make up the sea anemone.
Have the clownfishes and predators wait outside the classroom.
Have the sea anemone group make a circle around the desk with the plate (for collected cookies), make sure to leave some room in between the students.
Explain to the sea anemone group that they are to let the clownfishes enter and exit the circle, but they must keep the predators out. Leave other desks empty.
Explain to the clownfishes that they can move about freely, but the circle will act as a safety area.
Have the clownfishes enter and let them wander about the room. Let the predators in and have them tag the clownfishes. (no running)
If they touch the circle they must give a cookie to the circle.
Once a predator looses it's cookie, he must sit down inside the circle.
The activity should last about 10 minutes.

Images, work sheets, additional web pages

{none available}

Items for discussion or conclusion

1st question

What made the clownfishes go inside the cicle or sea anemone?

2nd question
What were the predators not allowed to do?

3rd question
How did the sea anemone help the clownfish and vice versa?

4th question
What is the relationship between the sea anemone and the clownfish called?


This activity should show how the clownfish and the sea anemone have a symbiotic relationship. The students should be able to see how the sea anemone protected the clownfish, and how the clownfish lured the predator became prey for the sea anemone

Beyond the Activity
Further activities which relate to and extend the complexity of the experiment.

Sea anemones, also, have symbiotic relationships with other organisms such as the hermit crab. Identify the relationship. (The crab is a transporter for the sea anemone, and the sea anemone is used for protection.)

Or exploring other symbiotic relationships between marine animals. Some animals act as transportation and others act as cleaners.

Web Resources
A web address with information on the topic of the activity.

Web Address

Additional References

Shick, J. Malcolm. A Functional Biology of Sea Anemones. Chapman and Hall. New York, 1991.