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Dive Photo Guide


Kobudai: Photographing the Transgender Fish
By Fabrice Dudenhofer, October 23, 2020 @ 08:00 AM (EST)

The charismatic Asian sheepshead wrasse—otherwise known as the Kobudai

The oceans contain their fair share of the planet’s strange creatures. Typically, the strangest aren’t accessible by divers because they live deep in the abyss. A few of these little-known species, however, evolve in affordable depths. Among them, we can count, without a doubt, the kobudai.

I heard about this special fish for the first time in 2009, with the release of the documentary Oceans, Jacques Perrin’s extraordinary film showcasing to sea lovers, and to the general public, various relatively unknown sea creatures. Kobudai, the name given by the Japanese to the Asian sheepshead wrasse (Semicossyphus reticulatus), likes shallow rocky habitats or wrecks, and feeds on mollusks and crustaceans. While most commonly found in the waters of Japan, it is also present in South Korea and China. But regardless of its location, the kobudai is more often captured by fishermen than it is observed in its natural environment by divers.

Eh, who are you calling “strange”?


A Face Only a Mother Could Love

The adult male exhibits a very particular physique. With its bulging chin and disproportionate forehead, this species of Labridae inevitably attracts comparison with “Elephant Man” Joseph Merrick. Semicossyphus reticulatus is also one of the largest wrasses known, along with its cousin the humphead wrasse (Cheilinus undulatus): The biggest specimens of kobudai can grow to well beyond three feet and weigh more than 30 pounds.

Juveniles and females, on the other hand, exhibit a somewhat more conventional appearance. Their scales are brighter in color, and they don’t have protruding facial adornments like the males—just a slight bump on the forehead. More fearful than males, they live hidden in crevices and are therefore more difficult to approach.

Females have a much less pronounced bump

As bulbous appendages go, Kobudai is king

Many of us were introduced to this curious creature by watching the documentary series Blue Planet II. To investigate the fascinating transformation of the sheepshead wrasse, the BBC film crew headed off the west coast of Japan to Sado Island. Knowing that the fish was a member of the Labridae—a well-known family that exhibits sequential hermaphroditism—the series producer, John Smith, wasn’t surprised that the kobudai changed its gender. “In many cases, sex change represents a normal biological process, a very reproductive strategy, common in many fish. For example, the humphead wrasse starts life as a female before eventually becoming a male, while others, like clownfish, will pass from male to female.”

Capturing Kobudai

Filming or photographing the kobudai is a challenge. When the Blue Planet II team went to Japan in 2016 to work with a local underwater film crew, they quickly discovered that it was rather difficult to approach this shy animal using open-circuit scuba. Returning the following year armed with rebreathers, the much-quieter BBC cinematographers were able to spend more time underwater with their subjects.

Big, bold males will come in close if you’re patient

A fisheye lens will really do justice to that beautiful face

For my part, I was able to photograph this extraordinary fish on scuba thanks to the experience and advice of local guides, including Yoshifumi Aihoshi, who has in-depth knowledge of the species and knows exactly where to encounter them without much difficulty. The kobudai is generally found between around 65 and 80 feet deep, sometimes less. Both off Sado Island in Niigata Prefecture and Yotsujima Island in Yamagata Prefecture, they are always present in more or less the same spots on the reef. Visibility is usually from 15 to 50 feet, depending on conditions.

It is important to remain as discreet as possible when approaching the kobudai. Since the fish are not fed, it is rare for them to come within inches of your camera. With a little patience, however, some individuals, mainly large males, can get quite close. A good option is a wide-angle zoom such as the Olympus 7–14mm f/2.8 Pro (14–28mm equivalent focal length), which I paired with my Olympus OM-D E-M1 Mark II.

With certain extremely curious individuals—probably attracted by their sublime reflection in my dome port—I managed to get close-ups with the Olympus 8mm f/1.8 Pro (16mm equivalent) fisheye lens. I tried to hold my breath until the fish got close enough to take their portrait; if you blow bubbles, your subject will immediately turn around. This is not a fish with silvery scales that reflect light, but care must be taken not to overexpose the white part of the head with your strobes.

Females tend to hide in crevices, so they present an excellent opportunity for a contextual shot

Sex Change in Fish

Hermaphroditism is far from exceptional in fishes. It affects about 2% of species, which represents more or less 500 different species around the world. There are generally two forms of hermaphroditism. In the first case, mature individuals, possessing functional male and female gonads at the same time, can mate with any adult individual of their species.

In the second case, members of the species also have both male and female gonads, but only one type of gonads is functional at any given time. Individuals are first sexually immature and then exhibit characteristics of one of the two sexes (the primary sex). Then, at some point in their life (depending on age, size, sex ratio, temperature and salinity of the sea, and so on), the gonads of the primary sex are inhibited and those of the secondary sex become active. The specimen thus “changes” sex; in reality, though, the fish has always been a carrier of both sexes.


This second type of hermaphroditism is described as successive. The initially female species are called protogynous (grouper, anthias, and of course, kobudai), while those that start male are called protandrous (the classic example being clownfish). In fish, protogyny is much more widespread—about nine times more—than protandry.

The kobudai may look like a freak from the deep, but it can be photographed at recreational diving depths  

Male kobudai keep an eye on each other from a comfortable distance


A True Playboy

No species of fish physically transforms like the kobudai. Diving instructor and biology enthusiast Yoshifumi Aihoshi, who manages Urban Sports in Yamagata Prefecture on the edge of the Sea of Japan, has followed the evolution of one particular individual over several years: “I have been diving for 18 years with Kinjiro [Jiro means “second son” in Japanese], a male that I’ve seen grow and transform off the islet of Yotsujima.” As Yoshifumi has observed, the physical transformation of the fish takes place over several months. The kobudai reaches sexual maturity as a female between three and six years. The larger ones are over 10 years old before they become males and can then live to about 40 years. “Today, Kinjiro must be around 30 years old,” says Yoshifumi, “and is asserting himself as the dominant male.”

Once the physical upheaval is over, the male kobudai adopts much more bellicose behavior, especially when the rising sea temperature—typically about 78°F, compared to around 47°F in winter—triggers the breeding season, which runs from May to mid-July. This aggressive demeanor will now push him into fierce battles with the older alpha male for dominance of the territory and access to females. Akihiro Yamada, a dive guide on Sado Island, tells me he knows a male at the head of a harem of about 15 females. So, say what you like about the photogenic qualities of these fascinating fish, but it would seem that the kobudai have no trouble wooing the girls.

Isn’t that a visage that every shooter should have in their portfolio?

The author would like to extend a special thanks to Urban Sports (Yamagata) and Ogi Diving Center (Sado Island). To see more of Fabrice’s awesome underwater images, check out his website, www.fabricedudenhofer.com, or his Instagram page. Fabrice has also been featured as a DPG Photographer of the Week.


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