Triacanthidae, commonly known as triplespines or tripodfishes, is a

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

fishes. It is classified in the order

Tetraodontiformes The Tetraodontiformes are an order of highly derived ray-finned fish, also called the Plectognathi. Sometimes these are classified as a suborder of the order Perciformes. The Tetraodontiformes are represented by 10 extant families and at least ...

, along with the

pufferfish Tetraodontidae is a family of primarily marine and estuarine fish of the order Tetraodontiformes. The family includes many familiar species variously called pufferfish, puffers, balloonfish, blowfish, blowies, bubblefish, globefish, swellfi ...

es and the

ocean sunfish The ocean sunfish or common mola (''Mola mola'') is one of the largest bony fish in the world. It was misidentified as the heaviest bony fish, which was actually a different species, '' Mola alexandrini''. Adults typically weigh between . The sp ...

. The family consists of seven species in four

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial ...

, in addition to one extinct genus that only is known from fossils. Much like their relatives the triggerfish and the

filefish The filefish (Monacanthidae) are a diverse family of tropical to subtropical tetraodontiform marine fish, which are also known as foolfish, leatherjackets or shingles. They live in the Atlantic, Pacific and Indian Oceans. Filefish are closely ...

, the triplespines's first ray of the

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through c ...

is formed to a spine. Further, they have two spines in place of their

ventral fin Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous Homology may refer to: Sciences Biology *Homology (biology), any characteristic of biological organisms that is der ...

s. They have sharp and heavy teeth, which they use to eat hard-shelled molluscs and crustaceans. They also have the unique ability to see ultraviolet light. Their ability to see ultraviolet light is similar to the vision of

Goldfish The goldfish (''Carassius auratus'') is a freshwater fish in the family Cyprinidae of order Cypriniformes. It is commonly kept as a pet in indoor aquariums, and is one of the most popular aquarium fish. Goldfish released into the wild have b ...

. Not much is known about how the fish live. They are essentially offshore fish that only come close to land occasionally. They range from in length.

Fossil record

The genus ''

Acanthopleurus ''Acanthopleurus'' is an extinct genus of prehistoric bony fish that lived during the early Oligocene epoch. See also * Prehistoric fish * List of prehistoric bony fish A ''list'' is any set of items in a row. List or lists may also refer to: ...

'' is known from the species ''A. serratus'' Agassiz, 1844 and ''A. collettei'' Tyler, 1980 of the

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but ...

of Glarus canton, Switzerland. A third described species ''Cephalacanthus trispinosus'' Ciobanu, 1977 from the Oligocene of

Romania Romania ( ; ro, România ) is a country located at the crossroads of Central, Eastern, and Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, Serbia to the southwest, Moldova to the east, a ...

, formerly in the family

Dactylopteridae The flying gurnards are a family, Dactylopteridae, of marine fish notable for their greatly enlarged pectoral fins. As they cannot literally fly or glide in the air (like flying fish), an alternative name preferred by some authors is helmet gurn ...

, has been considered to be a juvenile specimen of ''Acanthopleurus'', though whether it belongs with one of the two described species or a new species is not yet determined.Tyler, J.C., Jerzmariska, A., Bannikov, A.F. & Swidnicki, J. (1993):
Two New Genera and Species of Oligocene Spikefishes (Tetraodontiformes: Triacanthodidae), the First Fossils of the Hollardiinae and Triacanthodinae
''Smithsonian Contributions To Paleobiology, 75''

Eye ring coloring

Depending on the sex the colored ring around the outside of the

eye Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conv ...

is different. This fish is identified

female Female (symbol: ♀) is the sex of an organism that produces the large non-motile ova (egg cells), the type of gamete (sex cell) that fuses with the male gamete during sexual reproduction. A female has larger gametes than a male. Females a ...

if the ring color is purple or yellow and

male Male (Mars symbol, symbol: ♂) is the sex of an organism that produces the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or ovum, in the process of fertilization. A male organism cannot sexual reproduction, repro ...

if the ring is blue or orange. The frequency of these colors is different for each gender.

Black coral

Where there is

black coral Antipatharians, also known as black corals or thorn corals, are an order of soft deep-water corals. These corals can be recognized by their jet-black or dark brown chitin skeletons, surrounded by the polyps (part of coral that is alive). Antip ...

it is likely that one will be able to spot a Triacanthidae. They feed off of Black Coral. This is why the Triacanthidae is mostly found around

Northern Australia The unofficial geographic term Northern Australia includes those parts of Queensland and Western Australia north of latitude 26° and all of the Northern Territory. Those local government areas of Western Australia and Queensland that lie p ...

and

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

. Most fish are unable to feed off of Black Coral however their sharp and heavy teeth enable them to break the membrane of the Coral and access the rich nutrients that most fish cannot get to. This particular species of fish has been greatly decline due to harvesting of Black Coral. The graph below shows how the number of Triacanthidae began greatly decreasing in 1990 when harvesting Black Coral for sale first gained popularity. The species was dying rapidly until just recently in 2006 when a law banned the harvesting of Black Coral. The graph below shows then number of fish estimated for each year on the x-axis.

Numbers decline due to black coral harvesting

References

{{Taxonbar, from=Q1057142 Tetraodontiformes Marine fish families Taxa named by Pieter Bleeker