How Does a Male Clownfish Become Female?

Everyone "knows" about clownfish thanks to the Disney-Pixar film Finding Nemo. In fact, according to National Geographic, sales of clownfish have tripled since the release of the film in 2003. Given that Finding Nemo was a kid’s movie, there were a lot of things left out regarding the actual nature of a clownfish. For example, did you know that all clownfish are born male? So, how do we get female clownfish?

Incredibly, male clownfish can actually become female, because they carry both male and female reproductive characteristics. To get more technical – a male clownfish can dissolve its testes, while ovaries form from latent ovarian cells. Once they make the change, it’s permanent.

Clownfish live in groups, led by a female alpha. She is the largest fish, while the dominant male is the second largest. The remaining males in the group are smaller. If the female alpha dies, the dominant male will make the switch to female, while the largest of the smaller males will become the dominant male. This ensures the continued existence of these unique and beautiful fish.

Clowning around: