Rainbow Fish Discovered Deep in the Maldives Born Female then Transitions Into a Male as It Grows Older

The rainbow fish, born female but eventually turning into a male, was found in the depths. Only by utilizing specialized diving equipment were Maldivian researchers able to reach the rose-veiled fairy wrasse.

There are flashing shoals of vividly colored, finger-length fish all over the Maldives, between 40 and 70 meters (130-230 feet) beneath the Indian Ocean. These fish never venture up to the coral reefs at the surface.

Diving in the Depths

Deep-diving researchers have discovered several species in the mesophotic (or twilight) zone, located between the daylight shallows and the deep, dark ocean. One of these species is the rose-veiled fairy wrasse (Cirrhilabrus finifenmaa). It descends roughly 150 meters and is home to a unique species assemblage.

From a research ship in the Indian Ocean, Yi-Kai Tea, a postdoctoral scholar at the Australian Museum Research Institute in Sydney, writes via email that "the mesophotic zone is one of the least investigated places in coral reefs." This location is typically at an uncomfortable depth that is too deep to dive using regular scuba techniques, too complicated to be explored by trawling and dredging, yet not deep enough to be surveyed by submarines.

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Using Special Equipment

Scientists employ specialized diving equipment that circulates exhaled air rather than blowing bubbles directly into the water as typical scuba divers do to take pictures and collect specimens in the mesophotic zone. Rebreather divers may extend their dives to 100 meters by carefully regulating the gas mixture, removing excess carbon dioxide, and adding additional oxygen as needed.

To safely decompress from these extreme depths, they must remove many large gas cylinders and spend hours rising slowly. Still, in doing so, they might discover creatures that were previously unknown to science in this remote area.

Majestic Fishes

The pink rose, which shares the same species name as the rose-veiled fairy wrasse, and the colorful fish, finifenmaa, which means rose in the native Dhivehi language, were both referenced in the naming of the fish in 2022. Ahmed Najeeb of the Maldives Marine Research Institute is one of the researchers that helped locate and name the new wrasse. According to Tea, this is the first time a Maldivian scientist has described a new species endemic to the area.

Like other wrasse species, the rose-veiled fairy wrasse changes its sex and appearance as it ages. They are born female, develop into males, and become much more colorful as they age. The guys dress in magnificent nuptial hues to entice ladies during mating season.

The California Academy of Sciences' Hope for Reefs effort focuses on mesophotic reefs and seeks to understand better and conserve the world's coral reefs, including the discovery.

Similar Fish

In 2019, Tea gave a name to a second fairy wrasse found in the mesophotic zone off the Tanzanian island of Zanzibar. Cirrhilabrus wakanda, a species of vibranium fairy wrasse, with bright purple scales that change to a bright yellow color as the females become males.

The name is a tribute to Wakanda and the fictional superhero Black Panther. According to Tea, the wrasse has avoided research because it dwells on distant, hidden reefs far below the surface, much like the mysterious mythical country of Wakanda. The mythical rare metal vibranium is integrated into Black Panther's armor. He adds that the colors and patterns also made him think of the Wakandan costumes from the film.

Although they are still common, the rose-veiled fairy wrasse's stunning colors in the Maldives have proven alluring. They are already being taken from the wild for the decorative aquarium trade. According to what we know, they are not in immediate danger, says Tea.