| Clownfish |
| Clown Fish Are Fascinating |
Scientific Studies Have shown
Why and How They Change
Their Gender and Live Their
Entire Life Within Another
Species.
Why and How They Change
Their Gender and Live Their
Entire Life Within Another
Species.
The clownfish Amphiprion percula lives within the tentacles of sea anemones in small, size-ranked
groups of up to six individuals, with a single breeding pair. Their size and status is determined by
their function. Breeding pairs are the largest and rank the highest within the group that live in an
anemone and non-breeders are the smallest and lowest ranking clown fish. Only one breeding pair
can exist within one sea anemone and their numbers remain small. Scientists believe that all
individuals living within one anemone are genetically related.
Within each sea anemone there can be only one mated adult pair, and the rest are immature
individuals or larval. Their social ranking within their group biologically controls the sexes of the
fish. Scientists are still trying to understand how this occurs.
Sea Anemones More on Sea Anemones
The sea anemone is an animal that attaches itself to a rock and uses the stinging cells on its long,
brightly colored tentacles to kill prey. Because clown fish are immune to the stings, they can live
within the tentacles of an anemone, where they are also safely out of reach of predators.
Anemones provide clownfish with protection from predators. If anemonefishe are threatened by
predators, they quickly return to the safety of their anemone’s tentacles. If they do not return
to the safety of the anemone’s tentacles they are readily attacked and eaten by predators.
However, they rarely leave their anemone home and their overall rate of mortality amongst
these fishes is low. Female clown fish have a long life expectancy, living up to 30 years. Sea
anemones can also live up to 30 years old.
By comparison, life expectancy for damselfishes Pomacentrus wardi is 10 years, 11 years for
Dascyllus albisella, 15 years for Parma victoriae, 15 years for Stegastes altus, 17 years for
Hypsypops rubicunda and 17 years for Pomacentrus moluccensis. This means A. percula lives two
times longer than other damselfishes.
Clown Fish Breeding Rights and Gender
Each group of clown fish living within one anemone has a strict social order. The breeding female
is at the top with the breeding male next in the “pecking order”. The rest are nonbreeding and
are usually related and are always smaller that the top clown fish.
When the dominant clown fish female dies, every other fish in the group takes a step up the
social ladder. The male that was below the female grows bigger and switches sex to become the
breeding female. The nonbreeding member that was next in line grows bigger too and becomes a
male. The other fish also expand in size and move up the ladder. A new nonbreeder is recruited to
occupy the vacant rung at the bottom.
How do clown fish change from male to female?
In general, the female is the largest in size and is dominant in the group. If a dominant female
dies or is absent, the male partner undergoes a sex change to become a female.
A group consisting of a mated pair (dominant female and male) were made, sex change occurs in
an immature male. Scientiststs have shown that male gonadal development into a female is
triggered by the removal of the dominant female which causes the hypothalamic-pituitary glands
to increase Gonadotropin-releasing hormones (GnRHs). This hormone takes about 3 months to
complete the sex change from an immature male into the dominant breeding female.
Did You Know That Clownfish Make Sounds?
A male clownfish makes "pop-pop-pop" sound when he sees an intruder by opening his jaw, lifting
his head and causing ligaments to snap his jaw closed to make his teeth smack together.
Can Hear The Sounds Of Others In Their Group?
Yes, research has shown that they have the sensory ability to detect the frequencies in the
sounds they make. The frequencies in their calls and the ranges that they can hear is between 75
and 1800Hz, but they were most sensitive to frequencies below 200Hz.
Clownfish can only join the group living within an anemone when it is in the larval stage. Those at
the lower rank may move up the social hierarchy when dominant members die.
Social Structure In The Clownfish
Each group of A. percula has a well-defined social structure. Within each group, there is a
dominance hierarchy based on size; the female is largest (rank 1), the male is second largest
(rank 2), and the non-breeders are successively smaller (rank 3 to 6). However, research
studies show that size may be determined by rank. It is believed that clownfish have the ability
to adjust their size via food intake and rate of growth, with individuals with lower rank staying
small. The breeding pair are large by comparison.
Sex Changing Fish
Amphiprion percula is a protandrous hermaphrodite; if the female of a group dies, the male
changes sex and assumes the position vacated by the female, and the largest non-breeder from
the anemone inherits the position vacated by the sex-changing male
The size-based dominance hierarchy reflects a queue for breeding positions. That is to say, new
recruits enter a group at the bottom of the hierarchy and only move up through the hierarchy as
those ahead die. An individual only becomes female (rank 1) by queuing through the entire
hierarchy in its anemone.
Culturing Clownfish
Amphiprion species are some of the most popular marine fish among aquarium hobbyists and are
considered a beginner’s fish with regards to ease of maintenance and breeding. Here, it is shown
that frenatus embryos can be readily cultured in a simple laboratory set-up.
Clownfish (c. 12 cm length) can be maintained in artificial sea water (ASW; Instant Ocean) at a
salinity of 30, and a temperature of 25◦ C, in an (50 l) aquarium with a recirculating system
using pump biofiltration, constant aeration and protein skimmers. Fish can be fed frozen krill
twice daily, with any uneaten food removed by siphoning. A plastic pipe and several ceramic tiles
can be provided for environmental enrichment purposes. Eggs are laid at 3–4 week intervals in
batches attached to the glass walls of a tank.
Studies have shown that a single breeding pair of A. frenatus, will lay 50–200 eggs three times a
month. The yolk of A. frenatus embryos are orange-red in colour, similar to the coloration of the
adult fish. There was accumulation of black matter in the yolk.
Developing Clown Fish Embryos
(Amphiprion frenatus)
Although adult anemonefishes live for up to 30 years, they stay in the same area migrating less
than 100 meters.
Why Do Poisonous Anemone Allow Clownfish To Live Within Their Tentacles?
It is believed that the layer of mucus covering clownfish protects them from being stung by the
tentacles of sea anemones.
Anemone’s survival is improved with the presence of the clownfish. After the anemone eats his
prey the clownfish cleans up the waste products around and among the anemone’s tentacles.
The anemone enjoys better water circulation from the swimming movement of the clownfish
among its tentacles. If an enemy fish comes to eat the anemone, the clownfish becomes
aggressive, bares its teeth and makes noises.
The clownfish has bright colors that attract the anemone’s favorite prey, which it promptly
stings and shocks with the nematocysts located on the tentacles.
Luckily, the clownfish does not get stung by the poisonous anemone because they have a thick
layer of mucus covering their body which protects them from being stung by the anemone.
The anemonefish (clown fish), are dependent upon the anemone for protection and nutrition,
constituting a discrete habitat patch that provides a necessary and limiting resource. The
anemone is similarly dependent upon the clown fish for nutrients and protection. It is a true
"mutualism" in action. Copyright 2012.
References
Buston PM (2003a) Size and growth modification in clownfish. Nature, vol. 424.
Buston PM (2003c) Morality is associated with social rank in the clown anemonefish. Marine
Biology, vol. 143.
Elliott JK, Mariscal RN (2001) coexistence of nine anemonefish species: differential host and
habitat utilization, size and recruitment. Marine Biology, vol. 138.
Fautin DG, Allen GR (1992) Field Guide to Anemonefishes and Their Host Sea Anemones.
Holbrook SJ, Schmitt RJ (2005) Growth, reproduction, and survival of a tropical sea anemone
(Actinaria): benefits of hosting anemonefish. Coral Reefs, vol. 24.
Mariscal RN (1970) The nature of the symbiosis between Indopacific anemonefishes and sea
anemones. Marine Biology, vol. 6.
Moyer JT (1986) Longevity of the anemonefish Amphiprion clarkia at Miyake-jima, Japan, with
notes on four other species. Copeia, 1986, vol. 135.
groups of up to six individuals, with a single breeding pair. Their size and status is determined by
their function. Breeding pairs are the largest and rank the highest within the group that live in an
anemone and non-breeders are the smallest and lowest ranking clown fish. Only one breeding pair
can exist within one sea anemone and their numbers remain small. Scientists believe that all
individuals living within one anemone are genetically related.
Within each sea anemone there can be only one mated adult pair, and the rest are immature
individuals or larval. Their social ranking within their group biologically controls the sexes of the
fish. Scientists are still trying to understand how this occurs.
Sea Anemones More on Sea Anemones
The sea anemone is an animal that attaches itself to a rock and uses the stinging cells on its long,
brightly colored tentacles to kill prey. Because clown fish are immune to the stings, they can live
within the tentacles of an anemone, where they are also safely out of reach of predators.
Anemones provide clownfish with protection from predators. If anemonefishe are threatened by
predators, they quickly return to the safety of their anemone’s tentacles. If they do not return
to the safety of the anemone’s tentacles they are readily attacked and eaten by predators.
However, they rarely leave their anemone home and their overall rate of mortality amongst
these fishes is low. Female clown fish have a long life expectancy, living up to 30 years. Sea
anemones can also live up to 30 years old.
By comparison, life expectancy for damselfishes Pomacentrus wardi is 10 years, 11 years for
Dascyllus albisella, 15 years for Parma victoriae, 15 years for Stegastes altus, 17 years for
Hypsypops rubicunda and 17 years for Pomacentrus moluccensis. This means A. percula lives two
times longer than other damselfishes.
Clown Fish Breeding Rights and Gender
Each group of clown fish living within one anemone has a strict social order. The breeding female
is at the top with the breeding male next in the “pecking order”. The rest are nonbreeding and
are usually related and are always smaller that the top clown fish.
When the dominant clown fish female dies, every other fish in the group takes a step up the
social ladder. The male that was below the female grows bigger and switches sex to become the
breeding female. The nonbreeding member that was next in line grows bigger too and becomes a
male. The other fish also expand in size and move up the ladder. A new nonbreeder is recruited to
occupy the vacant rung at the bottom.
How do clown fish change from male to female?
In general, the female is the largest in size and is dominant in the group. If a dominant female
dies or is absent, the male partner undergoes a sex change to become a female.
A group consisting of a mated pair (dominant female and male) were made, sex change occurs in
an immature male. Scientiststs have shown that male gonadal development into a female is
triggered by the removal of the dominant female which causes the hypothalamic-pituitary glands
to increase Gonadotropin-releasing hormones (GnRHs). This hormone takes about 3 months to
complete the sex change from an immature male into the dominant breeding female.
Did You Know That Clownfish Make Sounds?
A male clownfish makes "pop-pop-pop" sound when he sees an intruder by opening his jaw, lifting
his head and causing ligaments to snap his jaw closed to make his teeth smack together.
Can Hear The Sounds Of Others In Their Group?
Yes, research has shown that they have the sensory ability to detect the frequencies in the
sounds they make. The frequencies in their calls and the ranges that they can hear is between 75
and 1800Hz, but they were most sensitive to frequencies below 200Hz.
Clownfish can only join the group living within an anemone when it is in the larval stage. Those at
the lower rank may move up the social hierarchy when dominant members die.
Social Structure In The Clownfish
Each group of A. percula has a well-defined social structure. Within each group, there is a
dominance hierarchy based on size; the female is largest (rank 1), the male is second largest
(rank 2), and the non-breeders are successively smaller (rank 3 to 6). However, research
studies show that size may be determined by rank. It is believed that clownfish have the ability
to adjust their size via food intake and rate of growth, with individuals with lower rank staying
small. The breeding pair are large by comparison.
Sex Changing Fish
Amphiprion percula is a protandrous hermaphrodite; if the female of a group dies, the male
changes sex and assumes the position vacated by the female, and the largest non-breeder from
the anemone inherits the position vacated by the sex-changing male
The size-based dominance hierarchy reflects a queue for breeding positions. That is to say, new
recruits enter a group at the bottom of the hierarchy and only move up through the hierarchy as
those ahead die. An individual only becomes female (rank 1) by queuing through the entire
hierarchy in its anemone.
Culturing Clownfish
Amphiprion species are some of the most popular marine fish among aquarium hobbyists and are
considered a beginner’s fish with regards to ease of maintenance and breeding. Here, it is shown
that frenatus embryos can be readily cultured in a simple laboratory set-up.
Clownfish (c. 12 cm length) can be maintained in artificial sea water (ASW; Instant Ocean) at a
salinity of 30, and a temperature of 25◦ C, in an (50 l) aquarium with a recirculating system
using pump biofiltration, constant aeration and protein skimmers. Fish can be fed frozen krill
twice daily, with any uneaten food removed by siphoning. A plastic pipe and several ceramic tiles
can be provided for environmental enrichment purposes. Eggs are laid at 3–4 week intervals in
batches attached to the glass walls of a tank.
Studies have shown that a single breeding pair of A. frenatus, will lay 50–200 eggs three times a
month. The yolk of A. frenatus embryos are orange-red in colour, similar to the coloration of the
adult fish. There was accumulation of black matter in the yolk.
Developing Clown Fish Embryos
(Amphiprion frenatus)
Although adult anemonefishes live for up to 30 years, they stay in the same area migrating less
than 100 meters.
Why Do Poisonous Anemone Allow Clownfish To Live Within Their Tentacles?
It is believed that the layer of mucus covering clownfish protects them from being stung by the
tentacles of sea anemones.
Anemone’s survival is improved with the presence of the clownfish. After the anemone eats his
prey the clownfish cleans up the waste products around and among the anemone’s tentacles.
The anemone enjoys better water circulation from the swimming movement of the clownfish
among its tentacles. If an enemy fish comes to eat the anemone, the clownfish becomes
aggressive, bares its teeth and makes noises.
The clownfish has bright colors that attract the anemone’s favorite prey, which it promptly
stings and shocks with the nematocysts located on the tentacles.
Luckily, the clownfish does not get stung by the poisonous anemone because they have a thick
layer of mucus covering their body which protects them from being stung by the anemone.
The anemonefish (clown fish), are dependent upon the anemone for protection and nutrition,
constituting a discrete habitat patch that provides a necessary and limiting resource. The
anemone is similarly dependent upon the clown fish for nutrients and protection. It is a true
"mutualism" in action. Copyright 2012.
References
Buston PM (2003a) Size and growth modification in clownfish. Nature, vol. 424.
Buston PM (2003c) Morality is associated with social rank in the clown anemonefish. Marine
Biology, vol. 143.
Elliott JK, Mariscal RN (2001) coexistence of nine anemonefish species: differential host and
habitat utilization, size and recruitment. Marine Biology, vol. 138.
Fautin DG, Allen GR (1992) Field Guide to Anemonefishes and Their Host Sea Anemones.
Holbrook SJ, Schmitt RJ (2005) Growth, reproduction, and survival of a tropical sea anemone
(Actinaria): benefits of hosting anemonefish. Coral Reefs, vol. 24.
Mariscal RN (1970) The nature of the symbiosis between Indopacific anemonefishes and sea
anemones. Marine Biology, vol. 6.
Moyer JT (1986) Longevity of the anemonefish Amphiprion clarkia at Miyake-jima, Japan, with
notes on four other species. Copeia, 1986, vol. 135.
Anemonefish (clown fish) populations are
entirely dependent on the availability of
suitable host anemones for habitat and
protection.
If they stray from their anemone like the
clown fish on the right, predators quickly
come along and eat them.
entirely dependent on the availability of
suitable host anemones for habitat and
protection.
If they stray from their anemone like the
clown fish on the right, predators quickly
come along and eat them.
Clown Fish Larvae (at
right) Are the Only Ones
That Can Enter An
Inhabited Sea Anemone
right) Are the Only Ones
That Can Enter An
Inhabited Sea Anemone
The clown fish will attack and eat many fish
that come within reach. The anemone gets the
leftovers after the clown fish finishes his
meal. Clown fish Waits at Lower Left.
that come within reach. The anemone gets the
leftovers after the clown fish finishes his
meal. Clown fish Waits at Lower Left.
Scientific Research
Articles:
Clown Fish
Sea Anemones
Seahorses
Coral Propagation
Articles:
Clown Fish
Sea Anemones
Seahorses
Coral Propagation