Some fish are born with only one gender and stay that way during their lives. Other fish, on the other hand, can change their gender. Some even can switch between two genders when necessary. This is called sequential hermaphrodites. It is predicted that there are roughly 2% of fish that can change gender. The following are the top ten fish that change gender.
1. Clownfish
Speaking of fish that change gender, clownfish is top of mind for many people. These fish are sequential hermaphrodites, which means that they are born males and later transform into females.
Another distinguishing aspect of these fish is that they live in groups and establish a hierarchal structure in which the female is the leader. The largest in the school is the female, the second largest is the male, and the rest fish are immature breeding males. The female controls the group, making sure that no fish will become bigger and turn into females.
Thanks to this dominant hierarchy, clownfish do not fight for breeding like other fish. If the female is no longer living due to predators or other causes, the dominant male fish that changes gender becomes the leader. You can see more about clownfish facts on our website.
The biggest male in the group at that time will become the dominant male once his sex organs have fully developed.
2. Asian sheepshead wrasse
The next fish that changes gender is the Asian sheepshead wrasse. This species is also called Kobudai and is one of the largest types of wrasse. They are found in the western Pacific Ocean and inhabit stony reefs.
The most noticeable thing about this fish is its face. It has a huge head hump and a weird face. Sometimes, its face looks like that of a human.
Kobudai is sequential hermaphrodite species. However, it will switch from female to male, instead of male to female like clownfish. This wrasse change not only its gender but also its appearance to sustain the ecology.
You can read our “7 amazing facts bout Kobudai” to see how this fish change gender.
3. Hawkfish
Hawkfish (Cirrhitidae) live on tropical reefs in the Pacific and Indian oceans. Like other fish in the list of fish that change gender, hawkfish can also change their sex. However, their ability is a little better than that of the others. What distinguishes it is that they can change their gender and reverse the process.
These brightly colored inhabitants begin as females and transform into males as needed. They live in harems, with a dominant male breeding with multiple females.
If the male hawkfish take on too many female partners, the largest female in the harem will transform into a male and takes charge of 50% of the females. Unlike Kobudai or clownfish, hawkfish don’t keep the male gender for the rest of their lives after changing. They can return to their original gender.
If some females in the group go to other harems or are challenged by a huge male, the male hawkfish will turn back to the female.
This ability contributes to the maximization of their reproductive capacity.
4. Green clown goby
The broad-barred goby is a coral reef fish living in the Indian Ocean. These fish are appealing due to their brilliant blue-green hue with red-orange patterns.
They are among the ocean fish that change gender. Being hermaphrodite species, they can also change their gender in both ways like hawkfish. This means they can change to male or female.
Due to this ability, they are one of the least endangered animals in the ocean. They don’t have to find opposite-sex partners. Two broad-barred gobies meet, one of them changes their sex to fit the other partner, and they start spawning.
Because of their captivating appearance, these fish are frequently caught in the ocean for the exotic pet trade. To learn more about this fish, read our “The green clown goby facts” article.
5. Ribbon eel
The ribbon eel is a member of Moray eels species. With a long, slender body with prominent dorsal fins. The eel resembles a fabled Chinese dragon. They are easily identified by their enlarged anterior noses which is similar to seahorses’ noses.
These eels can be found off the coasts of southern Japan, East Africa, Australia, and the Indo-Pacific Ocean.
These eels are born males. When the time comes, the eels will change gender to female. During their development, not only do the fish change sexes, but they also change their colors. To see how ribbon eels vary their colors through each stage, you can follow our article.
Ribbon eels don’t live long in tanks. They require special care.
6. Lyretail anthias
Lyretail Anthias, sometimes known as sea goldies, are a popular exotic fish species in the aquarium due to their brilliant colors and appealing body form. They are found throughout the Indo-Pacific region.
Lyretail anthias, like hawkfish, has a harem of 1 male and 5 – 10 females. When the male is absent for any reason, the female will turn into a male. To find out more information about sea goldies, you may read our article.
Its color will also change. The female fish come in brilliant orange coloration and a purple-orange stripe going across the eyes, similar to Cleopatra. When it changes to male, its body is red-orange or purple-pink, depending on where it’s from.
Furthermore, the male also displays superiority over the female by extending a spike on its dorsal fins.
7. Bluehead wrasse
Besides the Asian sheepshead wrasse, there is another wrasse fish that change gender – the bluehead wrasses (Thalassoma Bifasciatum). They are reef-dwelling fish of the Caribbean Sea and its surrounding waters.
Bluehead wrasses are either male or female at birth. The females will transform into males if necessary.
Gender transition in these fish is triggered by social factors. When the superior male fish dies, the greatest female fish switches into a male.
The trigger for gender change in these fish is social reasons. Once the dominant male fish is no longer alive, the largest female fish detects the lack of the male and changes to the male. And it immediately performs the male mating behavior.
8. Potter’s angelfish
The potter’s angelfish, commonly known as russet angelfish or pygmy angelfish, is a member of the Pomacanthidae family. It’s a marine ray-finned fish that change gender in the Central Pacific Ocean. They primarily inhabit coral reefs and graze on algae and debris.
These protogynous hermaphrodite sepcies are born females. When growing up, the fish with a huge body size will go through a gender transition and become a male.
9. Black sea bass
The black sea bass is one of the fish that change gender in the ocean. It belongs to the family Serranidae and is found in the Western Atlantic Ocean.
This fish starts its journey with the female gender. And then it eventually transforms into a male between 2 to 5 years old. However, the reason behind this and the specifics of how it occurs remain unknown. It’s thought that when the female notices that the male local population has decreased, it switches genders.
10. Humphead wrasse
Last but not least – the humphead wrasses. Another wrasse is on the list of fish that switch gender. This is the biggest member of the Labridae family. It can reach a size of 6 feet in length and weighs about 400 pounds.
Like other species in the list, they are protogynous hermaphrodites. This fish can change its gender, from female to male. Their coloring changes as well as their gender; the reddish-orange hue will turn to vivid blue-green coloration.
They live in the Indo-Pacific region on reefs. Their main diet includes mollusks, reef fish, crustaceans, and other invertebrates.
Conclusion
Those are 10 types of fish that change gender naturally. They are called hermaphroditic and can change sexes to boost their reproductive opportunities. This feature makes them unique.
However, some fish continue to change gender as a result of pollution. Fish that have been subjected to hormone-disrupting water contamination can change their sexes. In the testes of male fish, female egg cells are developing. This phenomenon is known as “intersex” and is happening all over the world, including in wildlife sanctuaries.
