You’re in for a treat if you think clownfish’s temperament was the only thing Pixar’s Finding Nemo did wrong. The film would not have been made if its makers had not listened to what really happens under the blue oceanic blanket. There would be many twists to the plot, including sexchange and incest.

These elements are far from the Disney-Pixar films, aren’t they?

You probably already know the answer. Let’s continue with the main question.

Can Clownfish Change Gender?

Yes, clownfish can alter their gender. Fish don’t have the same genders that we do. Let’s move on to the word “sex”. Yes, clownfish can switch their sex from male-to-female if they have the chance. Once you’re a female, there is no going back. It’s a one way ticket.

More than 30 species of clownfish live in the sparkling waters of the Indian Ocean and Red Sea.

All of them are hermaphrodites. Clownfish can be gender-bending marvels.

All fish of these species have the ability to change their sex to become females. However, all fish are born male at birth.

It sounds confusing, I’m sorry. Oder, “Confusing” might be more contextual.

This is how I felt first.

This blog was supposed to be simple. It would feature a few trivial facts and marvels of nature. Boy, was I wrong!

Throughout my research, I was bombarded by journals, endless forum threads and tabloid pieces discussing the whys and hows of a clownfish changing its gender.

Lucky for you, I tried to make this article as simple as possible, while making sure that you get the most important bits of this amazing, almost unfathomable phenomenon.

Why Do Clownfish Change Genders?

Clownfishes are sequential hermaphrodites. Clownfish are just one of hundreds of species of fish that can undergo sexual transition. Clownfish can change their gender to become dominant females in a group.

Let’s start by talking about this “group”. There are some similarities between bees and clownfish in certain aspects.

By the way, I assume you all are familiar with the adorable interspecies friendship between anemones and clownfish.

An anemone can house a lot of clownfish. The size and temperament of the clownfish will determine how many there are. This is a topic for another day.

The largest male in a group becomes a female. Only the largest and most aggressive male in the group will she mate with. The remaining members of the community are sexually immature males.

The breeding male will gain weight and be the first in the pecking list if the alpha female is lost or dies. He will soon be a she.

The next step is for every fish to grow and move up in rank. As you can see, the male breeder will be the largest non-breeder fish.

Size does matter, even if you are a clownfish. The size of an individual determines their worth and rank in the group.

So that the juveniles don’t rebel against their authority, the breeding couple will’suppress’ their maturation in the anemone.

The suppression occurs in subtle ways. For example, the breeding male seizes the lion’s portion of food to keep his body bulky.

It’s obvious that humans think of fish as nothing more than protein-rich, floating in the ocean. We don’t know how complex their thoughts and behaviors are.

Scientists believe the relationship between hierarchy and size has a lot in preventing conflicts between members of a group. This allows subordinates to not rise to power and threaten their ‘queen’ or ‘consort.

The breeding pair may even kill or expel non-breeders who show signs of rapid growth.

Before I explain why and how clownfish evolved to have sex with other species, let me address a question I’ve been asking you for a while.

How Would The Film’ Finding Nemo’ End If It Was Based On Clownfish’s Real Behavior?

First, Nemo is unlikely to get lost because clownfish rarely stray far from their host anemone.

Nemo’s mother gets eaten by barracuda so the breeding male, also known as Nemo’s father Marlin would have become a female. Marlyn, probably.

Thus, Nemo would become the largest non-breeding male and the ‘breeding man’. You can now fill in the gaps yourself…

Why Can Clownfish Change Their Gender?

It’s amazing to witness the sexual transition. It turns out that it is not unusual. Around 2% of fish species can exhibit some degree of hermaphroditism. This is roughly 500 species around the world.

To return to the original question, the social structure and ability of clownfish to have sex with other people can be attributed to their habitat choice – the sea anemone.

These stationary animals and clownfish share a unique symbiotic relationship. The toxic host is used by the fish to repel predators and find food scraps. The anemone uses fish poop as bait and nutrition.

If it wasn’t for the anemones, clownfish would have been an easy meal for any fish larger than them. These fish are small and brightly colored. They also have a very efficient swimming style.

Marlins are rarely seen leaving their hosts due to the presence of barracudas, large fish and other large fish. This means that it would be extremely difficult to find a female to join the group after the alpha matriarch has passed away.

A clownfish’s unique ability of changing sex means that it doesn’t need to travel to unknown territories in search of a mate.

Evolution is so insane, isn’t he?

How Can Clownfish Change Gender?

Because they are sequential hermaphrodites, clownfish can switch genders. Clownfish are born with both male & female reproductive organs. Hormonal change governs the biological transition from a breeder male into a female.

It is important to remember that while the DNA of the fish doesn’t change, the expression of various genes can change dramatically.

The most obvious change happens in the set of genes involved in the expression of gonadotropin-releasing hormones (GnRH), which regulate the gonad’s function in fish.

The testes are dissolved and the ovaries develop. This doesn’t happen overnight.

The latest study also shows that male-to female sex change happens first in the brain, and then only later involves the transformations of the gonads. Sometimes this occurs after a delay of several months or even years.

Frequently Asked Question

What Is It Called When Clownfish Change Gender?

Sexual hermaphrodism refers to the phenomenon of clownfish male to female transitions.

Are All Clownfish Born Male?

All clownfish are born male. But, as they mature, the biggest and most assertive clownfish in the group becomes a female.

How Many Times Can Clownfish Change Gender?

Clownfish are able to change their gender once. This change is permanent. You can’t turn back to a male once you have become a woman.

Be aware that only the largest fish in a group can become a female. Females may not be the destiny of all males.

It sounds dramatic, but a male clownfish must have the words written in its star to be a female.

Will The Biggest Clownfish Always Become Female?

It is possible that a small male might become a female.

How Quickly Can Clownfish Change Gender?

Clownfish do not change their sex overnight. It takes several weeks. It could take several months.

As sex changes progress, male gonads will lose more testicular tissue as well as ovarian tissue.

One study found that the male fish took over 50 days for their bodies to become highly degenerated and have reduced testes.

What Happens When You Pair Two Male Clownfish In The Tank?

It will be a showdown if you put two clownfish together in the tank. They will fight until one fish is clear. You know the drill. The winner becomes a woman.

Do Clownfish Mate With Their Offspring?

It’s not unusual for parents to mate in fish’s worlds with their offspring. It also applies to clownfish.

Many people who study fish and other stuff claim that, if Finding Nemo were to be based upon their actual behavior and practices, Marlin could have become a female and Nemo would fertilize her eggs.

Do Male Clownfish Eat Their Eggs?

A male clownfish will eat eggs from its eggs if it feels they are not going hatch or have not been fertilized. He will therefore stay close to the eggs and fan them until they hatch.

Final Words: Can Clownfish Change Gender?

It is possible. Clownfish can be sequential hermaphrodites. By dissolving their testes, they can transform from male to female and develop ovaries.

All of them are born males but the largest fish in the group will become a female. The breeding male will be the second-largest fish.

This phenomenon, while fascinating, is not uncommon. According to reports, 2% percent of all fish species exhibit some form of hermaphroditism.