Ribbonfish are fish with elongated, narrow bodies that live in the pelagic zone of marine waters. This means that they generally live in the open sea, not in the shallower coastal waters. Their typical habitat is at depths between approximately 330 ft (100 m) and 1,640 ft (500 m).
For biological classification, ribbonfish belong to the order lampriformes, under the suborder taeniosomi and in the family trachipteridae. Within the family, there are three genera and ten species. The ribbonfish genera are zu, desmodema, and trachipterus.
Ribbonfish are seldom seen because of the depths they inhabit. When they are observed, however, they are easily recognizable. Their slender, stretched-out bodies have a long dorsal fin, which typically runs down the whole length of the back, from just behind the head. They can have between 62 and 111 vertebrae. Anal fins are not present, and their pectoral fins are small. They also do not have scales.
Since they live in deeper waters, the fins and membranes of these fish are delicate and brittle. They move in a serpentine way, relying on their bodies’ undulations and their dorsal fins to propel them through the water. They are not bottom-feeders, and their diet consists mainly of fish, squid, and small invertebrates. An interesting characteristic they possess is that their jaws can significantly protrude when they are eating. They also grow in an allometric fashion, with different body parts growing at greatly varying rates.
Their habitat includes all the world’s oceans except the Antarctic. They also can be found in the Mediterranean Sea. Some places where ribbonfish have been caught include the Atlantic Ocean — near Iceland, Scotland, the Orkney Islands, and Scandinavia — as well as the Bay of Bengal, Puget Sound, and off of the coast of Mauritius. They can vary in length from 12 in (30.48 cm) to 56 ft (17.07 m).
One species of ribbonfish, trachipterus ishikawae, is also known as the earthquake fish by the Taiwanese people. This is because it tends to appear along the coast of Taiwan after a sizeable earthquake occurs. This has been documented in the years 2006, 2007, and 2010. Sightings of the fish have also occurred in the same area, however, when no seismic activity was recorded.
Another species of this pelagic fish is the trachipterus altivelis. Its common name is king-of-the-salmon, and it can be found in the waters of the Puget Sound. A Native American legend states that this ribbonfish leads the salmon when they migrate.