Pineapplefish
Encyclopedia
The pineapplefish, Cleidopus gloriamaris, is a species of fish
in the family Monocentridae
, and the sole member of its genus. It is also known as the knightfish or the coat-of-mail fish, due to the armor-like scales covering its body, and the port-and-starboard light fish, as it has a pair of bioluminescent organs
that are reminiscent of navigation light
s on ships. Its specific epithet is from the Latin
gloria and maris, meaning "glory of the sea".
, New South Wales
, and Western Australia
. It occurs at a depth of 6–200 meters (20–660 ft) in reef
s and harbors.
The pineapplefish grows up to 22 cm (8.7 in) long. It has a plump, rounded body almost completely covered in large, rough scales with sharp, backward-pointing spines. The head is large, with mucous
pits bordered by rough ridges, and is armored with heavy bone. The snout is blunt and overhangs the wide mouth
. The teeth are tiny and thin, present on the jaws, palatine, and vomer. There are two pits containing bioluminescent
bacteria
on the lower jaw near the corners of the mouth
, which are concealed when the mouth is closed. This photophore
is green in young fish and becomes more red as it ages. The first dorsal fin
consists of 5-7 strong spines; the spines are free of a membrane and point alternatingly left and right. The second dorsal fin contains 12 soft rays. Each pelvic fin contains an enormous spine, nearly as long as the head, and 3-4 rudimentary rays. The pelvic spine can be locked erect at a right angle to the body. The anal fin contains 11-12 rays and the pectoral fins 14-15 rays.
The scales of the pineapplefish are yellow to whitish with black rear margins, forming the striking pattern that gives this fish its name. The lips, chin, and parts of the jaw are black. There is a red stripe on the lower jaw running to the photophore. This species is very similar to the pinecone fishes of the genus Monocentris, and is placed within that genus by some authors. Cleidopus differs from Monocentris in having a narrow preorbital bone
and in the position of its light organs, which are near the tip of the lower jaw in Monocentris. This species also differs from the Japanese pineapplefish
(Monocentris japonica) in having a more rounded snout.
, a small group of pineapplefish has been documented under the same ledge for at least 7 years, and another group under a different ledge for 3 years. At night, this species ventures out onto sandy flats to feed, using its light organs to illuminate small shrimp
. The light may also be used to communicate with conspecifics. The light of the pineapplefish is produced by symbiotic
colonies of the bacteria Vibrio fischeri
within its photophores. V. fischeri are also found free-living in sea water and are naturally released from the pineapplefish's photophores. However, their luminescence dims a matter of hours after being released. This species has lived up to 10 years in captivity.
. It is fairly hardy, but must be provided with rocky hiding places and live food.
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
in the family Monocentridae
Monocentridae
Pinecone fishes are small and unusual beryciform marine fish of the family Monocentridae. The family contains just four species in two genera, one of which is monotypic. Their distribution is limited to tropical and subtropical waters of the Indo-Pacific...
, and the sole member of its genus. It is also known as the knightfish or the coat-of-mail fish, due to the armor-like scales covering its body, and the port-and-starboard light fish, as it has a pair of bioluminescent organs
Photophore
A photophore is a light-emitting organ which appears as luminous spots on various marine animals, including fish and cephalopods. The organ can be simple, or as complex as the human eye; equipped with lenses, shutters, color filters and reflectors...
that are reminiscent of navigation light
Navigation light
A navigation light is a colored source of illumination on an aircraft, spacecraft, or waterborne vessel, used to signal a craft's position, heading, and status...
s on ships. Its specific epithet is from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
gloria and maris, meaning "glory of the sea".
Distribution and habitat
The pineapplefish is native to coastal waters off QueenslandQueensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
, New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
, and Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
. It occurs at a depth of 6–200 meters (20–660 ft) in reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
s and harbors.
Description
Mucus
In vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. Mucous fluid is typically produced from mucous cells found in mucous glands. Mucous cells secrete products that are rich in glycoproteins and water. Mucous fluid may also originate from mixed glands, which...
pits bordered by rough ridges, and is armored with heavy bone. The snout is blunt and overhangs the wide mouth
Mouth
The mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....
. The teeth are tiny and thin, present on the jaws, palatine, and vomer. There are two pits containing bioluminescent
Bioluminescence
Bioluminescence is the production and emission of light by a living organism. Its name is a hybrid word, originating from the Greek bios for "living" and the Latin lumen "light". Bioluminescence is a naturally occurring form of chemiluminescence where energy is released by a chemical reaction in...
bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
on the lower jaw near the corners of the mouth
Mouth
The mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....
, which are concealed when the mouth is closed. This photophore
Photophore
A photophore is a light-emitting organ which appears as luminous spots on various marine animals, including fish and cephalopods. The organ can be simple, or as complex as the human eye; equipped with lenses, shutters, color filters and reflectors...
is green in young fish and becomes more red as it ages. The first 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...
consists of 5-7 strong spines; the spines are free of a membrane and point alternatingly left and right. The second dorsal fin contains 12 soft rays. Each pelvic fin contains an enormous spine, nearly as long as the head, and 3-4 rudimentary rays. The pelvic spine can be locked erect at a right angle to the body. The anal fin contains 11-12 rays and the pectoral fins 14-15 rays.
The scales of the pineapplefish are yellow to whitish with black rear margins, forming the striking pattern that gives this fish its name. The lips, chin, and parts of the jaw are black. There is a red stripe on the lower jaw running to the photophore. This species is very similar to the pinecone fishes of the genus Monocentris, and is placed within that genus by some authors. Cleidopus differs from Monocentris in having a narrow preorbital bone
Orbit (anatomy)
In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents...
and in the position of its light organs, which are near the tip of the lower jaw in Monocentris. This species also differs from the Japanese pineapplefish
Monocentris japonica
Monocentris japonica is a pinecone fish of the family Monocentridae, found in the tropical Indo-West Pacific oceans, at depths of between 10 and 200 m. Its length is between 8 and 15 cm.-References:...
(Monocentris japonica) in having a more rounded snout.
Biology and ecology
Due to its small fins and rigid armor, the pineapplefish is a weak swimmer. A nocturnal species, it may be found inside caves and under rocky ledges during the day. In the Fly Point Halifax Park Aquatic Preserve, New South WalesNew South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
, a small group of pineapplefish has been documented under the same ledge for at least 7 years, and another group under a different ledge for 3 years. At night, this species ventures out onto sandy flats to feed, using its light organs to illuminate small shrimp
Shrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
. The light may also be used to communicate with conspecifics. The light of the pineapplefish is produced by symbiotic
Symbiosis
Symbiosis is close and often long-term interaction between different biological species. In 1877 Bennett used the word symbiosis to describe the mutualistic relationship in lichens...
colonies of the bacteria Vibrio fischeri
Vibrio fischeri
Vibrio fischeri is a gram-negative rod-shaped bacterium found globally in marine environments. V. fischeri has bioluminescent properties, and is found predominantly in symbiosis with various marine animals, such as the bobtail squid. It is heterotrophic and moves by means of flagella. Free living...
within its photophores. V. fischeri are also found free-living in sea water and are naturally released from the pineapplefish's photophores. However, their luminescence dims a matter of hours after being released. This species has lived up to 10 years in captivity.
Relationship to humans
The pineapplefish is moderately common in deep water, but due to its retiring nature, for some time after its initial discovery it was only known from specimens tossed ashore by storms. This fish is sometimes collected by commercial trawlers, and is popular with saltwater fish aquaristsFishkeeping
Fishkeeping is a popular hobby concerned with keeping fish in a home aquarium or garden pond. There is also a fishkeeping industry, as a branch of agriculture.-Types of fishkeeping systems:...
. It is fairly hardy, but must be provided with rocky hiding places and live food.