''Kryptopterus vitreolus'', known commonly as the glass catfish, the glass cat, the ghost catfish or the phantom catfish, is a small

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of translucent-bodied, social glass catfish in the family

Siluridae Siluridae is the nominate family (biology), family of catfishes in the order (biology), order Siluriformes. About 105 living species of silurids are placed in 12 or 14 genera. Although silurids occur across much of Europe and Asia, they are most ...

. It is commonly seen in captivity and in the freshwater aquarium trade, although its official

taxonomy image:Hierarchical clustering diagram.png, 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme o ...

is still debatable, and was only truly resolved in 2013. Glass catfish are

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

, where they inhabit rivers and streams south of the Isthmus of Kra that drain into the

Gulf of Thailand The Gulf of Thailand (), historically known as the Gulf of Siam (), is a shallow inlet adjacent to the southwestern South China Sea, bounded between the southwestern shores of the Indochinese Peninsula and the northern half of the Malay Peninsula. ...

and river basins in the Cardamom Mountains. There are also unconfirmed reports from

Penang Penang is a Malaysian state located on the northwest coast of Peninsular Malaysia along the Strait of Malacca. It has two parts: Penang Island, where the capital city, George Town, is located, and Seberang Perai on the Malay Peninsula. Th ...

Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...

. Until 1989, ''K. vitreolus'' was considered to be the same as another "glass catfish", '' Kryptopterus bicirrhis'', a larger species that is not commonly seen in captivity. Additionally, ''K. vitreolus'' was believed to be the same as '' K. minor'' until 2013, when it was established that captive specimens actually represented another species, which is now named as ''K. vitreolus''. The true ''K. minor'', which is restricted to

Borneo Borneo () is the List of islands by area, third-largest island in the world, with an area of , and population of 23,053,723 (2020 national censuses). Situated at the geographic centre of Maritime Southeast Asia, it is one of the Greater Sunda ...

, has rarely, if ever, entered the aquarium trade.

Description and taxonomy

''Kryptopterus vitreolus'' is a small, transparent-bodied, freshwater-dwelling

catfish Catfish (or catfishes; order (biology), order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Catfish are common name, named for their prominent barbel (anatomy), barbels, which resemble a cat's whiskers, though not ...

with two long sensory barbels. Standard lengths for mature fish may range up to , but usually only reach around in total length. Their bodies are transparent because, like all catfish, they lack scales. Additionally, species in the genus ''Kryptopterus'' have no body pigment. The species' skin is made of a "

plywood Plywood is a composite material manufactured from thin layers, or "plies", of wood veneer that have been stacked and glued together. It is an engineered wood from the family of manufactured boards, which include plywood, medium-density fibreboa ...

"-like structure of

collagen Collagen () is the main structural protein in the extracellular matrix of the connective tissues of many animals. It is the most abundant protein in mammals, making up 25% to 35% of protein content. Amino acids are bound together to form a trip ...

fibrils, which allows for light to enter and diffract through the muscles. The majority of their organs are located near the head; with a

magnifying glass A magnifying glass is a convex lens—usually mounted in a frame with a handle—that is used to produce a magnified image of an object. A magnifying glass can also be used to focus light, such as to concentrate the Sun's radiation to create ...

, the

heart The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrie ...

can be seen beating. When the light strikes this fish at a certain angle, it can create an iridescent, rainbow effect. During acute periods of illness or after death, the tissues turn a milky-white. The specific name, ''vitreolus'', is derived from the

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''vitreus'', which means 'glass'. Among described species of ''Kryptopterus'', only two other species, ''K. minor'' and '' K. piperatus'', have clearly transparent bodies; these species are largely—if not entirely—absent from the aquarium trade. The bodies of other species in the genus, including ''K. bicirrhis'', are only somewhat translucent or opaque.

In mythology

According to Thai folklore, this species of catfish was born from Phra Ruang, the legendary king who had supernatural speech. It is said that after he ate a fish until only the bones were left, he then released it into the water and said that he wished it would come back to life. The fish was then returned to life with only its bones, as a glass catfish. Hence, it is also called ''pla kang phra ruang'' (, , "Phra Ruang's bones fish").

In captivity

The aquarium trade in ''K. vitreolus'' generally relies on wild-caught specimens, and there are concerns that this may be unsustainable due to the volume and its limited range. Unlike many other aquarium fish, it is not known to be bred at commercial facilities. One of the places where they are caught in the wild is the Phru To Daeng

peat swamp forest Peat swamp forests are tropical and subtropical moist broadleaf forests, tropical moist forests where waterlogged soil prevents dead leaves and wood from fully decomposing. Over time, this creates a thick layer of acidic peat. Large areas of th ...

, Narathiwat province in deep

south Thailand Southern Thailand (formerly Southern Siam and Tambralinga) is the southernmost cultural region of Thailand, separated from Central Thailand by the Kra Isthmus. Geography Southern Thailand is on the Malay Peninsula, with an area of around , bo ...

Electromagnetic response

''K. vitreolus'' reacts to electromagnetic fields owing to a protein encoded by Electromagnetic Perceptive Gene (EPG).

References

{{Taxonbar, from=Q13746133 Siluridae Fish of Thailand Endemic fauna of Thailand Fish described in 2013 Taxa named by Heok Hee Ng Taxa named by Maurice Kottelat

Description and taxonomy

In mythology

In captivity

Electromagnetic response

See also

References