Sarcastic fringehead

A small fish with a huge mouth

The sarcastic fringehead (Neoclinus blanchardi) is a small fish of the family Chaenopsidae. Its elongated, cryptic body looks ordinary until the fish flares its mouth: then it reveals extraordinarily large jaws that open like a huge, colourful parachute, gigantic in proportion to its body. The name "fringehead" refers to the fringed appendages that adorn its head above the eyes.

Habitat and range

It lives along the Pacific coast of North America, from California to Baja California, on sandy and muddy bottoms. It shelters inside dens: empty shells, abandoned burrows, tubes and even man-made objects such as cans or plastic pipes, with only its head poking out.

Behaviour

It is extremely territorial. When two males contest a shelter, they confront each other by flaring their huge mouths and pressing them together, almost as if kissing: this lets them compare the size of their jaws and settle who is stronger, the winner claiming the den. From its shelter the fish defends its space with lightning strikes, biting intruders far larger than itself.

Did you know?

Its gaping-mouth displays, spectacular and almost comical, have made it a small star of underwater documentaries. Despite its fierce look, it is entirely harmless to people, apart from a bite if carelessly handled.

Conservation

The IUCN lists it as Least Concern. It is not considered threatened, but like all coastal-bottom dwellers it depends on the quality of the water and marine habitats.