Why Are There So Many Male Clownfish?

Male clownfish can never throw a bachelor party. If a group of clownfish, also known by the scientific name Amphiprion percula, find themselves without a female, one of the males -- the largest of the group -- changes into one. This astonishing transformation was discovered by Cornell University researcher Dr. Peter Buston, who collected a small group of the fish and removed the lone female. Not only did he watch as the largest male changed his sex, but he also discovered why there is very little conflict among the fish. It turns out that clownfish have a very hierarchical society, and the largest clownfish is always a breeding female. Next in size is the breeding male, who is followed by other non-breeding males. When the female was removed, the male breeder became the female breeder, and the next-largest male became the male breeder. The other fish grew in size accordingly. This pattern guarantees that fighting for dominance has no place in the clownfish kingdom, Buston said. Although clownfish live all over the world, Buston focused on those living on a coral reef in Papua New Guinea.

Close-up of the clownfish:

• Technically speaking, Nemo's father in the popular movie Finding Nemo should have turned into a female after Nemo's mom died.
• Clownfish and sea anemones work together in habitats, with the fish removing parasites and the anemones providing shelter.
• While a clownfish's diet is mostly algae and zooplankton, they can also eat other animals, like worms and small crustaceans.