Hermaphroditism is a common condition among fish because of which they can change their gender under certain circumstances. So, which fish can change gender?
Fish that can change gender are:
- Chalk Bass,
- Mangrove Rivulus,
- Broad-Barred Goby,
- Potter’s Angelfish,
- Ribbon Eel,
- Kobudai (Asian Sheepshead Wrasse),
- Humphead Wrasse,
- Bluehead Wrasse,
- Black Porgy,
- Black Sea Bass, and
- Lyretail Anthias.
Let’s take a detailed look at each of these fish now to understand how they change gender.
Fish That Can Change Gender
Some fish species such as rays and sharks are born as one gender and remain the same throughout their lives.
In contrast, some other fish possess the gender reversal ability.
Following are the fish that can change gender.
Scientific Name: Amphiprioninae.
Found In: The Red Sea and the Pacific Ocean.
Clownfish are the most popular fish species when it comes to gender-changing ability.
They are sequential hermaphrodites, meaning they begin their life as males and then change into females once they mature.
Another distinctive feature of Clownfish is that they follow a dominance hierarchy, which means a powerful and aggressive female is at the top.
These fish usually live in groups. Only two Clownfish are active in a group, the largest female and the second largest male fish.
The rest of the Clownfish are small and reproductively immature males.
So unlike other fish species, they don’t compete among themselves for mating.
During the breeding season, the female and male Clownfish begin to reproduce.
However, if the female Clownfish is no longer alive due to predation or other reasons, the largest male Clownfish changes into a female.
After that, one of the inactive male Clownfish shows the willingness to reproduce and becomes the active male of the group.
Scientific Name: Serranus Tortugarum.
Found In: Western Atlantic Ocean.
Check out how Chalk Bass looks over here.
Chalk Bass is a species of marine ray-finned fish. These fish are famous for switching from female to male and back again.
Chalk Bass are relatively small fish that grow up to 3 inches but can change gender up to 20 times a day.
They are simultaneous hermaphrodites, meaning they simultaneously possess active male and female reproductive organs.
Mary Hart, the lead author of a study, told National Geographic that the reason for their frequent switching of gender is still unknown.
But it’s speculated that Chalk Bass change gender for reproductive advantage.
Scientific Name: Kryptolebias Marmoratus.
Found In: Coasts of Mexico, Florida, Central, and South America.
Check out how Mangrove Rivulus looks over here.
Mangrove Rivulus, also known as Mangrove Killifish, is a species of Killifish that falls under the Rivulidae family.
These fish mainly live in marine and brackish waters.
The unique feature of these fish is that they breed mainly by self-fertilization.
They are hermaphrodites, meaning they can self-fertilize by producing both sperm and eggs.
A female Mangrove Rivulus produces sperm and eggs and then turns into a male by reabsorption of the ovarian tissue.
Although female Mangrove Rivulus fish can change gender to male via reabsorption of ovarian tissue, they can’t switch back.
Scientific Name: Gobiodon Histrio.
Found In: Indian Ocean.
Broad-Barred Gobies are reef-dwelling fish found in the rocky reefs of the Indian Ocean.
These fish are attractive due to their vibrant blue-green color with reddish stripes and dots.
Another unique feature of Broad-Barred Gobies is that they are hermaphrodite species.
As a result, they can change gender both ways, from female to male and vice-versa.
When a pair of Gobies of the same gender colonize, one will change into the opposite gender.
Due to their enchanting look, these fish are often harvested from the wild for the aquarium trade.
Scientific Name: Centropyge Pottery.
Found In: Central Pacific Ocean.
Potter’s Angelfish, also known as Potter’s Pygmy Angelfish or Russet Angelfish, is a marine ray-finned fish belonging to the Pomacanthidae family.
These fish are born as females because of their protogynous hermaphroditism.
However, as they grow, the large-sized fish undergo a gender change to become male.
They mainly live in the coral reefs and feed on algae and detritus.
Scientific Name: Rhinomuraena Quaesita.
Found In: Indo-Pacific Ocean.
Ribbon Eels are species of Moray Eels resembling a mythical Chinese dragon. They have a thin, long body with high dorsal fins.
They can be easily recognized by their anterior nostrils that are expanded.
Every Ribbon Eel is born a male and can change gender. They can change into a female when the need arises in the future.
Ribbon Eels need special care and hence are preferred by experienced aquarists only.
Kobudai (Asian Sheepshead Wrasse)
Scientific Name: Semicossyphus Reticulatus.
Found In: Japan, across the western Pacific Ocean.
Kobudai, also known as Asian Sheepshead Wrasse, is a member of the Wrasse family. They mainly inhabit rocky reef habitats.
Kobudai exhibit sequential hermaphroditism, a process through which a creature not only changes its physical appearance under certain conditions but also its gender to maintain the ecology.
Unlike Clownfish that change gender from male to female, Kobudai change from female to male once they reach a particular size and age.
Scientific Name: Cheilinus Undulatus.
Found In: Coral reefs in the Indo-Pacific region.
The Humphead Wrasses are the largest living member of the family Labridae. They are protogynous hermaphrodites.
Female Humphead Wrasses can change to male. Along with gender change, their coloration also changes.
A female Humphead Wrasse that’s reddish-orange changes to bright blue-green color once it becomes a male.
These fish are giant and can grow up to 6 feet long and weigh a whopping 400 pounds.
They mainly feed on reef fish, crustaceans, mollusks, sea urchins, and other invertebrates in their natural habitat.
Scientific Name: Thalassoma Bifasciatum.
Found In: Coral reefs of the Caribbean Sea and its adjacent waters.
Bluehead Wrasses are another species of Wrasses that possess the gender reversal ability.
These wrasses are born as either male or female.
But the female Bluehead Wrasse can change to male if the need arises.
The trigger for gender change in these fish is for social reasons.
The largest female fish changes to male once the dominant male fish is no longer alive.
The female fish senses the absence of males and adopts complete male breeding behavior the same day.
Scientific Name: Cirrhitidae.
Found In: Tropical reefs of the Pacific Ocean and the Indian Ocean.
Hawkfish are one of the few fish species that can change gender and switch back again.
These vibrantly colored harem dwellers start as females that morph into males when the need arises.
They live in harems with one dominant male mating with several females.
Gender reversal happens mainly when the harem’s male leader takes on too many females.
In such instances, the largest female Hawkfish changes gender and turns into a male to take over half of the harem, mating as a male.
However, the female turned male Hawkfish doesn’t necessarily continue as male for the rest of its life.
Instead, it turns back to female if the other male Hawkfish loses a few females to other harems or if a large male challenges the females.
Their ability to undergo bidirectional gender change helps to maximize their reproductive value.
Scientific Name: Acanthopagrus Schlegelii.
Found In: Japan.
Check out how Black Porgy looks over here.
Black Porgy is bottom-dwelling fish inhabiting shallow temperate waters and tropical marine and estuarine waters.
They are born as males and can turn into females.
Research has found that a Black Porgy reproduces as male for the first two years of its life.
After a couple of years, around 50% of these fish change their gender to female.
Black Sea Bass
Scientific Name: Centropristis Striata.
Found In: Western Atlantic Ocean.
Black Sea Bass is a species of marine ray-finned fish belonging to the Serranidae family. They are protogynous hermaphrodites.
A Black Sea Bass begins its life as a female and switches to male later in life.
These fish can change gender from female to male once they attain the age of around 2 to 5 years.
However, the reason and details of how it happens are still unknown.
It’s speculated that their gender change is related to a decrease in the male population.
When a female Black Sea Bass observes that the local population of its male counterparts has declined, it changes its gender to male.
Scientific Name: Pseudanthias Squamipinnis.
Found In: Indo-Pacific region.
Lyretail Anthias is an exotic fish species that’re popular in the aquarium trade because of their vibrant colors and attractive body structure.
Female Lyretail Anthias turn into males in the absence of a dominant male in their natural habitat or aquariums.
There’s also a change in coloration when a female Lyretail Anthias switches to male.
The female fish is bright orange in color with a purple eyeliner like Cleopatra.
However, when it switches to male, the female fish turns bright purple.
In addition, it extends a spike on its dorsal fins to express dominance over its female counterparts.