Red-tailed black shark
Encyclopedia
The red-tailed black shark (Epalzeorhynchos bicolor), also known as the redtail shark and Labeo bicolor, is a species of freshwater
Freshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...

 fish
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 carp
Carp
Carp are various species of oily freshwater fish of the family Cyprinidae, a very large group of fish native to Europe and Asia. The cypriniformes are traditionally grouped with the Characiformes, Siluriformes and Gymnotiformes to create the superorder Ostariophysi, since these groups have certain...

 family, Cyprinidae. It is currently critically endangered
Critically endangered
Version 2010.3 of the IUCN Red List of Threatened Species identified 3744 Critically Endangered species, subspecies and varieties, stocks and subpopulations.Critically Endangered by kingdom:*1993 Animalia*2 Fungi*1745 Plantae*4 Protista-References:...

 in the wild, but common in aquaria, where it is prized for its deep black body and vivid red or orange tail.

Distribution

The species is endemic to Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...

, and was described by Hugh M. Smith in 1931 as being 'not uncommon' in Bueng Boraphet
Bueng Boraphet
Bueng Boraphet is the largest freshwater swamp and lake in central Thailand. It covers an area of 224 km² east of Nakhon Sawan, south of the Nan River close to its confluence with the Ping River....

 and the streams which lead from it, and as being found in the Menam Chao Phaya
Chao Phraya River
The Chao Phraya is a major river in Thailand, with its low alluvial plain forming the centre of the country. It runs through Bangkok, the capital city, and then empties into the Gulf of Thailand.-Etymology:...

 as far south as Bangkok. A 1934 expedition reported catching a specimen in the Silom canal. As of 2011 it is only known at a single location in the Chao Phraya basin, and has Critically Endangered status on the IUCN Red List. From 1996 until 2011 it was believed to be Extinct in the Wild. There is no evidence that collection for the aquarium trade is responsible for the species' decline, and it is more likely that construction of dams and draining of swamps that took place during the 1970s resulted in their decline.

Sexual dimorphism

It is notoriously difficult to sex redtail sharks. Females may have a grey belly, and males may have a more pointed dorsal fin, though there are some individuals with both these characteristics. Redtail sharks are usually spawned en masse in fish farms with artificially introduced hormones.

In the aquarium

In the aquarium trade, tail colors can vary, with bright red and orange being the most common. If the shark is stressed or unhealthy, the red color will drain from its tail. Albino forms may also be encountered.

pH and water temperature

In home aquaria, redtail sharks prefer a pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

 between 6.8 and 7.5, a temperature between 22°C and 26°C (72°F and 79°F) and water hardness
Hard water
Hard water is water that has high mineral content . Hard water has high concentrations of Ca2+ and Mg2+ ions. Hard water is generally not harmful to one's health but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling...

 between 5 and 15 dH.

Size

Red tail sharks can reach a length of 15 cm (6 inches), and can live up to eight years, although in some rare cases they have lived to be over 10 years old.

Aquarium size

The recommended aquarium size is at least 170 to 210 litres (45 gallons to 55 gallons). More aggressive redtails require larger aquariums. They are excellent jumpers, so require tight lids on the aquarium.

Compatibility and personality

Typically they are aggressive chasers, but will rarely bite or harm other fish. Individual personalities vary greatly - some are calm, while others are extremely aggressive and cranky. They are bottom dwellers and like lots of dark hiding places. They get along with other semiaggressive fish, but they do not like other sharks.

When two red tails cohabitate, they have been known to become extremely territorial with one another. One shark will become dominant and will continually chase and harass the submissive shark, preventing it from feeding and resting. This will often result in the death of the submissive redtail shark. Larger groups of five or more, surprisingly, tend to get along much better than two or three, as they will establish a stable hierarchy; such a group will require a very large aquarium, however.

Redtail sharks are considered compatible in some community tanks, although they may chase docile or peaceful fish that present a large target (such as the Metynnis argenteus
Metynnis argenteus
Silver dollar is a common name given to a number of species of fishes, mostly in the genus Metynnis, tropical fish belonging to the Characidae family which are closely related to piranha and pacu...

, or "silver dollar" fish). This may be harmless, but could cause a great deal of stress for the pursued fish, sometimes resulting in death due to stress (though this is rare). Redtails do not typically bite or injure other fish, but they will chase them and try to corner them. They will mostly chase fish away from their territory and then retreat; therefore, it is important to ensure the aquarium is large enough to allow the redtail some space to call its territory. Aquariums should be at least 170 litres (45 gallons) or larger for a comfortable community. Redtails are bottom dwellers, so it is highly suggested that one does not introduce them into an aquarium with another bottom dweller, as they will constantly pester and harass it. They also should not be introduced to communities containing other shark-like fish.
Redtail sharks have also been known to be excellent jumpers, so a tight-fitting lid on the aquarium is recommended.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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