Fish

Wrasses

All in the Labridae family

More than 500 species of wrasses—marine fishes that belong to the Labridae family—are found in the tropical and subtropical waters of the Indian, Pacific and Atlantic oceans. Here at the Aquarium, we have a variety of wrasse species in our care: the Christmas wrasse, sixline wrasse, cleaner wrasse, bird wrasse—and the largest wrasse species of them all, the humphead (also called Napoleon) wrasse. Keep reading to learn more about these amazing fish—then plan a visit to see them in person!

At the Aquarium

Wrasse class: now in session

Depending on species, wrasses make their homes in coastal areas, rocky shores, coral reefs, tide pools and the sandy ocean floor. While most have life spans of three to five years, humpheads, one of the largest of all reef fishes, may live longer than 30 years. Regardless of species, wrasses are confirmed carnivores. Their diets are based on invertebrates (animals without backbones) such as shellfish, snails, sea stars and sea urchins, as well as fish. And who eats wrasses? Their predators include lionfish, barracudas and sharks.

Labriform locomotion

Most fish species use their pectoral fins—located on their sides, just behind their heads—primarily for stabilization. But the majority of wrasse species rely almost entirely on those fins, instead of their caudal fins (tails), for propulsion. In fact, it’s enough of a signature that this kind of movement, called labriform locomotion, is named after the Labridae family. Some say that it makes the fish look more like they’re flying than swimming.

Wrasse pectoral fins work like oars, pushing the water backward in a powerful stroke that thrusts the fish forward. Then, during the recovery stroke, pectoral fins are held close to the body to reduce drag in the water as they return to their starting position.

Keeping it flexible

Many, if not all wrasse species are capable of changing sex from female to male. Most wrasses are born female and can change their sex as they grow older and larger. Why does this happen, when it does? Usually because of the loss of the dominant male, or if there are too many females. In those instances, the largest (formerly) female becomes male and takes control of the mating group so reproduction can successfully continue.

A (hump)head above the rest

In September 2025, the Seattle Aquarium welcomed a male humphead wrasse (Cheilinus undulatus) into our care. He spent some time getting acclimated at our off-site Animal Care Center until he was ready to make a move to the Ocean Pavilion. Before we introduce you to him, a few basics on this species:

As mentioned above, humpheads are the world’s largest wrasse species—males may grow to more than 6 feet long and weigh over 400 pounds!
They’re known for their beautiful, green-to-blue hues, brightly colored facial markings and big, circular scales.
Their common name comes from the large, bulbous hump that develops on the forehead of mature adult males.
Humpheads are listed as Endangered by the International Union for Conservation of Nature (of which the Seattle Aquarium is a proud member) and on Appendix II of CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) to control international trade.

Getting to know Tandu

In case you hadn’t guessed, Tandu is the name of the humphead wrasse in our care. He came to us from the Singapore Oceanarium, where he’d been living for four years—but his story begins before then. Captured in the wild, he was illegally trafficked and imported to Hong Kong. (Although humphead populations are carefully regulated because of their endangered status, they're a luxury food in some international markets and, as such, likely candidates for trafficking.)

Tandu was rescued in Hong Kong and spent about two years at Ocean Park Hong Kong. Because he was confiscated from traffickers, his original source location couldn’t be confirmed and it wasn’t possible to return him to the wild. After his time at Ocean Park Hong Kong, he moved to the Singapore Oceanarium and from there, to us. While in human care, he has been a key contributor to scientific and conservation research to protect his species from illegal trade. Keep reading to learn more!

Saving Face: a first-of-its-kind conservation tool

In human care, Tandu not only serves as an ambassador for his species—he’s also part of a new endeavor to protect it. Saving Face is a research project, led by Dr. Yvonne Sadovy and Dr. Loby Hau, focused on detecting and preventing humphead trafficking.

By photographing the facial markings of individual wrasses over time, Dr. Sadovy and Dr. Hau have demonstrated that each fish maintains its own unique markings—just as we humans have unique fingerprints—and the markings remain stable over time. This enables individuals to be identified and tracked by their facial markings—and checking these markings against a database allows authorities to determine if the fish was sold to a market without the proper permits.