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Dragonfishes and Relatives: Stomiiformes

Rat-trap Fish (malacosteus Niger): Species Accounts

Physical characteristics: Rat-trap fish are about 10 inches (25 centimeters) long. They are blunt on the ends, and the dorsal fin and anal (AY-nuhl) fin, or the fin along the midline of the belly, are well back near the tail fin. The body is solid black. The lower jaw is much longer than the skull and holds four pairs of large fangs. The mouths of these fish have no floor. The light organs on the body are very small. The eyes are large, and there is a large, deep-red light organ under each eye. There is no chin barbel.

Geographic range: Rat-trap fish live all over the world.

Habitat: Rat-trap fish live in the middle and deep parts of the open ocean day and night.

Diet: Rat-trap fish mainly eat small crustaceans but sometimes eat fish and shrimp.

Rat-trap fish can produce red light with the large light organs under their eyes. They can also see red light. (Illustration by Joseph E. Trumpey. Reproduced by permission.)

Behavior and reproduction: Rat-trap fish can produce red light with the large light organs under their eyes. They can also see red light. Because most deep-sea fishes can see only blue-green wavelengths, this ability helps rat-trap fish search for prey without being seen by predators. Scientists do not know much about the reproduction of rat-trap fish.

Rat-trap fish and people: Rat-trap fish have no commercial value, but they have been studied for medical purposes.

Conservation status: Rat-trap fish are not threatened or endangered. ∎



Hoyt, E. Creatures of the Deep. Buffalo, NY: Firefly, 2001.

Niesen, Thomas M. The Marine Biology Coloring Book. 2nd ed. New York: HarperResource, 2000.

Web sites:

"Dragonfish." All the Sea. http://www.allthesea.com/Deep-Sea-Fish-Dragonfish.html (accessed on September 27, 2004).

"Viperfish." Environmental Literacy Council. http://www.enviroliteracy.org/subcategory.php/231.html (accessed on September 27, 2004).

Additional topics

Animal Life ResourceFish and Other Cold-Blooded VertebratesDragonfishes and Relatives: Stomiiformes - Physical Characteristics, Behavior And Reproduction, Dragonfishes, Their Relatives, And People, Viperfish (chauliodus Sloani): Species Accounts - GEOGRAPHIC RANGE, HABITAT, DIET, CONSERVATION STATUS