The unicorn crestfish or unicornfish, Eumecichthys fiski, is a very rare, little-known species of crestfish

Crestfish

Crestfishes are lampriform fishes in the family Lophotidae. They are elongate ribbon-like fishes, silver in color, found in deep tropical and subtropical waters worldwide...

 in the family Lophotidae, and the only member of its genus. It likely has a worldwide distribution, having been first discovered offshore of Kalk Bay

Kalk Bay

Kalk Bay is a fishing village on the coast of False Bay, South Africa and is now a suburb of greater Cape Town. It lies in a beautiful setting, wedged between the ocean and sharply rising mountainous heights that are buttressed by crags of grey sandstone...

, South Africa

South Africa

The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

, and subsequently reported from the Sea of Japan

Sea of Japan

The Sea of Japan is a marginal sea of the western Pacific Ocean, between the Asian mainland, the Japanese archipelago and Sakhalin. It is bordered by Japan, North Korea, Russia and South Korea. Like the Mediterranean Sea, it has almost no tides due to its nearly complete enclosure from the Pacific...

, southwest Florida

Florida

Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...

, Clarion Island

Clarion Island

Isla Clarión, formerly called Santa Rosa, is the second largest, westernmost and most remote of the Revillagigedo Islands, west of Socorro Island and over from the Mexican mainland and an area ². It has three prominent peaks. The westernmost and tallest peak, Monte Gallegos, is high...

 off Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

, Hawaii

Hawaii

Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...

, and India

India

India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

. A report from the Bering Sea

Bering Sea

The Bering Sea is a marginal sea of the Pacific Ocean. It comprises a deep water basin, which then rises through a narrow slope into the shallower water above the continental shelves....

 may have been in error. It is found in the bathypelagic zone, at a depth of around 1,000 meters (3,300 ft).

This fish has ribbon-like body measuring up to 150 cm (59 in) in length. Its common name

Common name

A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...

 comes from a horn-like supraoccipital process projecting forward of its eyes. The upper jaw is protrusible, and the jaws contain small conical teeth. The dorsal fin

Dorsal fin

A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...

 runs along the entire length of the body and contains 310-392 soft rays; the first 3-5 dorsal rays at the tip of the projecting ridge are elongated into a pennant. The pectoral fins contain 13-15 rays; the pelvic fins are absent. The anal fin contains 5-9 rays and in adults is split lengthwise to form two rows of nubbins. The caudal fin contains 12-13 rays, with the bottommost ray enlarged and bony. The coloration is silvery with 24-60 dark sub-vertical bands. The dorsal and caudal fins are crimson.

Eumenichthys is one of three lampriform

Lampriformes

Lampriformes is an order of ray-finned fish. They are collectively called "lamprids" or lampriforms, and unite such open-ocean and partially deep-sea Teleostei as the crestfishes, oarfish, opahs and ribbonfishes...

 genera known to possess an ink tube

Ink sac

With the exception of nocturnal and very deep water cephalopods, all coeloids which dwell in light conditions have an ink sac, which can be used to expel a cloud of dark ink to confuse predators. This sac is a muscular bag which originated as an extension of the hind gut...

, allowing them to expel a black fluid from their cloaca

Cloaca

In zoological anatomy, a cloaca is the posterior opening that serves as the only such opening for the intestinal, reproductive, and urinary tracts of certain animal species...

 as a defense against predators. The ink tube is derived from a primitive gut

Gut (zoology)

In zoology, the gut, also known as the alimentary canal or alimentary tract, is a tube by which bilaterian animals transfer food to the digestion organs. In large bilaterians the gut generally also has an exit, the anus, by which the animal disposes of solid wastes...

 and runs above and parallel to the intestine

Intestine

In human anatomy, the intestine is the segment of the alimentary canal extending from the pyloric sphincter of the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine...

. A known predator of the unicorn crestfish is the longnose lancetfish, (Alepisaurus ferox); a lancetfish 73 cm (29 in) long has been found that had swallowed a unicorn crestfish 55 cm (22 in) long.