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Home › Facts about Sea Life › Marine Species › Vertebrates › Anemonefish

Fun Facts about the Clown Anemonefish

[Clownfish Phylum: Chordata] [Class: Actinopterygii] [Order: Blenniiformes] [Family: Pomacentridae]

The scientific name for the twenty eight (28) clown fish species is Amphiprioninae and they're best known for their symbiotic relationship with sea anemones.

This section contains fun facts about anemonefish (clownfish family Pomacentridae), such as where they live, what they eat, and how these cute saltwater fishes reproduce.

Clownfish Geographical Range and Habitats

The anemonefish species is native to the waters that span the western Pacific regions and the Indian Ocean, especially:

• Andaman Sea (e.g. Nicobar Islands, Malaysia, Thailand)
• Indonesia (including Bali, North Sulawesi)
• The Philippines
• Northern Australia (e.g. the Great Barrier Reef)
• Southern waters of Japan
• Sri Lanka (including the Maldive Islands)

The geographical range of anemonefish directly relates to the global distribution of the types of sea anemones that provide them with a safe habitat.

As a consequence, the best place to find the genus Amphiprioninae is around shallow coral formations, particularly lagoon reefs and sheltered coastal ecosystems shallower than twenty (20) metres (66 feet).

Pro Tip: Even though clownfishes are damselfishes that prefer to live in the warm waters of some tropical marine environments, they do not exist in the Caribbean Sea or the Atlantic Ocean.

Clownfish Anemone Characteristics

There are several physical characteristics that help identify the fish that live in anemones. First, anemonefishes are quite small and rarely grow longer than eleven (11) centimetres (4 inches).

Second, the predominant body colouration of the clownfish species is bright orange, some black, red, yellow, often with distinctive white bands, vertical bars, stripes, or patches.

But wait - there's more:

Even though the colours and patterns vary according to the actual species, one of the most common is the orange and white banded ocellaris clownfish (scientific name Amphiprion ocellaris).

By and large, the clownfish body shape is rounded with a somewhat blunted facial profile. Like their close relatives (the damselfish species) they also have relatively small fins for lively marine vertebrates.

Fun Fact: One of the clownfish's most interesting traits is being able to make colour changes. For example, some species can make a subtle change of colour in response to changing environmental conditions or with age.

Clown Fish Behaviour and Symbiosis

The "mutualistic" clownfish and sea anemone relationship is beneficial for both parties. For instance, it helps to provide the fish with some protection against their natural predators (moray eels) and it also ensures there is a plentiful supply of food scraps for the host anemone.

This only works because anemonefish are able to produce a special protective mucus layer that protects them from the stinging tentacles of sea anemones.

Despite the protection gained from living inside anemones, or because of it, clownfish are highly territorial and rarely wander far away from the host anemone.

Clownfish (Amphiprion) also have an unusual social structure.

Their strict dominance hierarchical system means the largest and most dominant will always be a female, and the second-largest will be a breeding male.

Interesting Fact: Clownfish only use ten (10) sea anemone species as hosts in their symbiotic relationships. But, some of the most common include the sebae anemone (Heteractis crispa), the magnificent sea anemone, and the bubble-tip anemone (Entacmaea quadricolor).

What Do Anemone Fish Eat?

Clown fish are "omnivores", so their daily diet is quite straightforward and focuses around various types of plant-based food.

Even so, they also consume various amounts of planktonic organisms, algae, copepods, zooplankton, and larval sea squirt tunicates.

Pro Tip: If you're keeping clownfish and anemone in an aquarium, they will eat a variety of prepared aquarium food diets, especially brine shrimp.

Types of Clownfish Species List

Clownfish Reproduction and Life Cycle

The unique and fascinating reproductive system of anemonefish (clownfish) involves a combination of sequential hermaphroditism and strict social hierarchy - followed up with strong parental care.

Even though the gender of all anemonefish is male when they are born, being protandrous hermaphrodites means they can change into females if, or when, it becomes necessary.

Here's the thing:

Each social group will have one dominant individual (e.g. the largest and most aggressive female). The breeding male will be the next largest in the congregation.

What if the dominant female dies? If so, the role is passed over to the breeding male, who changes gender and becomes a female. Hence, the next male in line gets promotion and becomes the new breeding male.

Courtship and Mating Ritual

The mating process occurs between the dominant female and the breeding male. In general, a display of courtship will include a combination of fancy fin displays, chasing, and nipping.

After they clean a suitable nesting site (such as a flat solid rock close to the anemone), the spawning and egg care can go ahead. Under optimum conditions, anemonefish can spawn every two (2) to four (4) weeks.

The female lays between one hundred (100) and one thousand (1000) eggs on the flat surface and encourages the male to fertilise them soon after.

Male Parental Care

Similar to damselfish reproduction, the male fans the eggs with his fins to enhance oxygen and he stands guard against unwanted intruders. It's also his duty to remove any unfertilised or dead eggs.

After six (6) to ten (10) days of incubation, the eggs start to hatch during the darkness, to reduce predation. The larvae will be free-floating for another seven (7) to twelve (12) days while they search for a host anemone and start their new life.

Clownfish Predators and Threats

In their natural oceanic environments, clownfish can live up to ten (10) years. Still, even though their symbiotic relationship with sea anemones affords them some protection, they become vulnerable to predation any time they move away from it.

Some of the main predatory marine creatures that eat anemonefish, include:

• Groupers
• Moray eels
• Sharks
• Snappers
• Wrasse fish

In addition, clownfish eggs and larvae often fall victim during the "free-floating" larval stage to crabs, sea stars, and certain kinds of planktivorous fish.

Other contributing factors for the decline in a few vulnerable areas include certain types of human behaviour such as, habitat destruction (e.g. coastal development), coral reef destruction, overcollection for the aquarium trade, and warming seas.

Pro Tip: Most of the anemonefish species are classified as "Least Concern" by the IUCN Red List of Threatened Species. But, they listed McCulloch's Anemonefish (Amphiprion mccullochi) as "Vulnerable" (VU) in 2021 with a population trend stated as "Decreasing".

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