Clownfish change their gender from male to female mainly for reproduction. The male clownfish change their gender to female when the group’s alpha female passes away. This gender change doesn’t happen overnight. It takes several months. It’s also a one-time process since the change is irreversible.
2 Main Reasons Clownfish Change Gender
Clownfish are sequential hermaphrodites.
They can change gender from male to female depending on the need and social environment they live in.
Although these fish have the unique ability to change gender, not all clownfish do so.
Many clownfish don’t change gender in their entire life.
Clownfish change gender mainly for the following two reasons.
One of the primary reasons for clownfish to change their gender is reproduction.
There is usually only one female in the group, which is usually the most dominating and aggressive.
The female clownfish mates with the most commanding male in the group, which is usually the breeding male.
Once the female clownfish of a group is no more, the breeding male transforms into a female so that the reproduction cycle isn’t disrupted.
This ability of clownfish to change gender has ensured their successful survival and increase in population.
2. Don’t Have to Search for A Mate
Clownfish and sea anemones share a symbiotic relationship in their natural environment.
Several clownfish form a group and stay close to the sea anemones for survival.
Since clownfish are tiny, they can be an easy meal for any large fish in the wild.
Staying close to the sea anemones protects them as they use the toxic tentacles of the sea anemones to defend themselves against predators.
They rarely leave their host anemones and live independently.
When the female clownfish of the group passes away, the males don’t find a new female to join their group.
Instead, the group’s dominant male becomes a female, and the next-in-line male becomes the breeding male.
This allows all the surviving clownfish to continue reproducing without having to stray from the group into unsafe waters where they can be easily predated.
When Do Clownfish Change Gender?
Clownfish change their gender when the dominant female of the group is no more.
Since all clownfish are born as males, one of the dominant males has to change its gender to female for reproductive purposes.
There is only one female in the group. The second largest and the most dominant male in the group is the reproductive male.
Once the alpha female clownfish of the group passes away, the reproductive male clownfish changes into a female to fill her position in the group.
The next dominant male in the group then becomes the reproductive male.
At this time, every male clownfish in the group moves up in the pecking order.
The newly formed clownfish pair breed until one of them is no more.
The gender-change cycle then continues until no more dominant female is left in the group.
How Do Clownfish Change Gender?
Clownfish being sequential hermaphrodites, are born with both male and female reproductive organs.
While switching from male to female, biological change is governed by hormonal change.
A study reveals that the male-to-female gender change first occurs in the brain of the male clownfish.
After several months, the transformation of gonads takes place.
The DNA of the clownfish doesn’t change during the transition.
But there is a change in the gene set responsible for the gonadotropin-releasing hormones (GnRH).
The gonadotropin-releasing hormones regulate the gonad’s function in the body of a clownfish.
During the gender change, the testes of the clownfish dissolve while the ovaries form.
This process stimulates the brain of the clownfish, which regulates its hormonal activity.
At this time, the male clownfish enters the transition phase and begins to change gender.
The transitioning male clownfish eats a lot of food at this stage to enhance its body size. It also increases its appetite.
Once the brain and gonads change entirely, the male clownfish changes completely into a female clownfish.
The gender change process completes at this point.
You can also notice a behavioral change in the clownfish as the female clownfish is usually very dominant over the male clownfish.
How Long Does It Take for Clownfish to Change Gender?
Clownfish don’t change gender overnight. The gender change process takes a lot of time and happens gradually.
It can take several weeks to months before the clownfish transforms completely into a female.
Initially, the male clownfish undergoing gender change needs to gain weight.
Hence, it gets the first food choice in the group and eats more than usual.
During this time, the male clownfish grows larger until it reaches full size.
Apart from the physical change, there is also a significant change in the brain activity level of the clownfish.
It’s also one of the reasons why the gender change process takes significant time.
The main changes that drive gender change development occur within 30 days of the passing of the original dominant female.
After around 3 to 4 months, the brain of the male clownfish changes entirely into a female.
The spawning process starts once the male clownfish transforms completely into a female.
How Many Times Do Clownfish Change Gender?
Clownfish can change gender only once in their lifetime. The change is permanent and irreversible.
However, you have to note that not all clownfish change gender.
The largest and most aggressive male clownfish that reach the top of the hierarchy change their gender from male to female.
When the alpha female passes away, the next largest male in the hierarchy changes to a female.
This process continues throughout the lifecycle of all the clownfish in a group.
Are All Clownfish Born Male?
Yes, all clownfish are born male.
However, they carry both male and female reproductive organs that allow them to change gender when necessary.
Can a Female Clownfish Reverse Back to Male?
A female clownfish can’t reverse to a male after the gender change. Clownfish follow a strict hierarchy in their natural habitat.
Since all clownfish are born as males, the most dominant among the group becomes a female.
There is also no reason for the female clownfish to reverse to male because many males are already waiting in the rank to claim dominance.