The Giant oarfish is a very particular abyssal fish. This fish has been reported in all seas and oceans having been found as far north as 72°N and as far south as 52°S, but is most commonly found in the tropics to middle latitudes.
It has an elongated and ribbon-like body, rather fragile, silver in color and streaked with dark oblique bars, with the skin covered with small tubercles. The short head is bluish. Juvenile individuals have a set of very fine teeth per jaw which disappears in adults.
It is characterized by a bright red dorsal fin that runs along its entire body, by the presence of a crest of rays placed above the head and by two long pelvic fins similar to oars. The main peculiarity of the Giant oarfish is undoubtedly its length: it can reach a length of 11 meters although normally it does not exceed 3 and, consequently, the weight can reach several quintals.
For this reason, it is considered by many to be the longest bony fish in the world. The size makes it almost immune to predators and are probably the origin of the legends that are told about sea monsters.
Giant oarfish, legends and curiosities
In February 2010, in the Gulf of Mexico, at a depth of about 1500 metres, a specimen was sighted by a bathyscaphe whose length was roughly estimated at over 17 metres.
The biology of the Giant oarfish is still poorly understood. It is undoubtedly an abyssal species (300–1000 m deep), but it is possible to locate it near the surface and near the coasts. Sometimes the regaleco is found beached but, due to its fragility, rarely intact.
Only in 2010 was it filmed in its natural environment, about 300 meters deep in the Gulf of Mexico. Due to their size, elongated bodies, and undulating swimming pattern, giant oarfish are presumed to be responsible for some sea serpent sightings.
Formerly considered rare, the species is now suspected to be relatively common, although sightings of healthy specimens in their natural habitat are unusual. Little is known about oarfish behavior. It has been observed swimming by means of its dorsal fin, and also swimming in a vertical position.
In 2010, scientists filmed a giant oarfish in the Gulf of Mexico swimming in the mesopelagic layer, the first footage of a reliably identified R. glesne in its natural setting. The footage was caught during a survey, using an ROV in the vicinity of Thunder Horse PDQ, and shows the fish swimming in a columnar orientation, tail downward.