The rainbow shark (''Epalzeorhynchos frenatum'') is a species of

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical south-eastern region of Asia, consisting of the regions that are situated south of mainlan ...

n freshwater fish from the family Cyprinidae. It is also known as the ruby shark, red-fin shark, red-finned shark, rainbow sharkminnow, green fringelip labeo, whitefin shark and whitetail sharkminnow.Red-fin Shark, Rainbow Shark, Ruby Shark (''Epalzeorhynchus frenatus''), Mongabay.com, 2006
retrieved on August 17, 2007Rainbow Shark (''Epalzeorhynchos frenatum''), AquariumLife.net (undated)
retrieved on August 17, 2007 It is a popular, semi-aggressive aquarium fish. Unlike true

shark Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachi ...

s, which belong to the

Chondrichthyes Chondrichthyes (; ) is a class that contains the cartilaginous fishes that have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fishes'', which have skeletons primarily composed of bone tissue. ...

("cartilagenous fishes") lineage, the rainbow shark is an actinopterygiian ("ray-finned fish").

Distribution and habitat

Rainbow sharks are native to the basins of

Mekong The Mekong or Mekong River is a trans-boundary river in East Asia and Southeast Asia. It is the world's twelfth longest river and the third longest in Asia. Its estimated length is , and it drains an area of , discharging of water annual ...

Chao Phraya The Chao Phraya ( or ; th, แม่น้ำเจ้าพระยา, , or ) is the major river in Thailand, with its low alluvial plain forming the centre of the country. It flows through Bangkok and then into the Gulf of Thailand. E ...

, Xe Bangfai and Maeklong in

Indochina Mainland Southeast Asia, also known as the Indochinese Peninsula or Indochina, is the continental portion of Southeast Asia. It lies east of the Indian subcontinent and south of Mainland China and is bordered by the Indian Ocean to the west an ...

. They live in water with sandy substrates, near the river bottom. This species feeds on algae and plankton, and seasonally migrates into flooded areas, then recedes back to the rivers as the floods dry up.

Description

The rainbow shark has an elongated black, dark blue or bright blue body. The snout is pointed. The abdominal area is flat. The fins possess red to orange-red coloration. The linear area from the gill cover, the eye, and the mouth has a characteristic brief stripe. Compared to females, male rainbow sharks have thinner bodies with black lines along the tailfins. Males also have brighter coloration. They can grow up to about long.

Variants

The albino red-fin shark or albino rainbow sharkminnow is a variety of rainbow shark with a white body and red/orange fins.Fenner, Bob. The Rainbow, Redfin and Albino Minnow Sharks, Epalzeorhynchos munense and E. frenatum, The Conscientious Aquarist, WetWebMedia.com (undated)
retrieved on August 17, 2007 It closely resembles "normal" rainbow sharks in temperament and appearance, thus they share the same common names in the aquarium industry.
retrieved on August 17, 2007 These have sometimes been referred to as '' E. munense'', but that is a separate species that rarely enters the aquarium trade. The rainbow shark is also one of the types of genetically modified, fluorescent fish known as

GloFish The GloFish is a patented and trademarked brand of genetically engineered fluorescent fish. They have been created from several different species of fish: zebrafish (''Danio rerio'') were the first GloFish available in pet stores, and recently te ...

Another variant that exists is a rarer form, often referred to as the “ghost sharkminnow”. Its appearance is otherwise identical to the typical rainbow shark, however its fins are white, and almost transparent

In the aquarium

Behavior

Rainbow sharks are tank-bottom and aquarium-surface cleaners. Being bottom- and mid-level dwellers, they consume leftover fish food, but also eat the algae growing off surfaces. They are known to be peaceful with their own kind in the wild but have been known to be aggressive with one another if kept together in a tank. Threat displays and fighting are likely to occur. This fighting behavior involves head-and-tail butting, and also biting.. A large rainbow shark will continuously chase a smaller one until the smaller one dies, or chase other fish out of its territory, especially in confined environments like aquaria. It may also increase the risk of the fish jumping out of its tank. This makes breeding difficult. The provision of hiding places and hollowed decors such as plants or artificial cave-like and tunnel-like aquatic ornaments minimize this typical behavior. Due to this behavioral characteristic among its own kind, rainbow sharks are not recommendable to the new aquarist. Keeping them with relatives, such as red-tailed sharks, bala sharks and black sharks should be avoided, as they will chase and attack them as well.

Tank requirements

An adult rainbow shark thrives in a minimum of 55 gallons of water, with an aquarium length of 48 inches, at the neutral pH range (6 to 8 pH), with temperatures between , and water hardness maintained at 5 to 11 dH. They must have this much space, as they frequently swim around quickly and will terrorize other fish in any tank under this size.

Compatibility

Rainbow sharks are compatible with barbs and

rainbowfish The rainbowfish or Melanotaeniidae is a family of small, colourful freshwater fish found in northern and eastern Australia, New Guinea (including islands in Cenderawasih Bay and Raja Ampat Islands in Indonesia), Sulawesi and Madagascar. The ...

, which are upper- and middle-tank dwellers. They can also live with

danio ''Danio'' is a genus of small freshwater fish in the family Cyprinidae found in South and Southeast Asia, commonly kept in aquaria. They are generally characterised by a pattern of horizontal stripes, rows of spots or vertical bars. Some species ...

s, loaches, plecos, rasboras, and

gourami Gouramis, or gouramies , are a group of freshwater anabantiform fishes that comprise the family Osphronemidae. The fish are native to Asia—from the Indian Subcontinent to Southeast Asia and northeasterly towards Korea. The name "gourami", of ...

s. They can be housed with some species of larger freshwater shrimp although any fry or eggs might get eaten by the shark. They are not compatible with smaller, more timid fish in the tank, as the sharks may terrorize them by chasing them from their territory.Rainbow Shark Information, TimsTropicals.com, 2007
retrieved on August 17, 2007

Diet

Rainbow sharks are picky

herbivorous A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpar ...

and

omnivorous An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nut ...

eaters but are primarily consumers of algae in the form of flakes. They also eat live foods, such as insect

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...

tubifex worms ''Tubifex'' is a cosmopolitan genus of tubificid annelids that inhabits the sediments of lakes, rivers and occasionally sewer lines. At least 13 species of ''Tubifex'' have been identified, with the exact number not certain, as the species ...

periphyton Periphyton is a complex mixture of algae, cyanobacteria, heterotrophic microbes, and detritus that is attached to submerged surfaces in most aquatic ecosystems. The related term Aufwuchs (German "surface growth" or "overgrowth") refers to the col ...

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...

s, phytoplankton,

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

and aquatic insects. Diet also include

lettuce Lettuce (''Lactuca sativa'') is an annual plant of the family Asteraceae. It is most often grown as a leaf vegetable, but sometimes for its stem and seeds. Lettuce is most often used for salads, although it is also seen in other kinds of food, ...

and spinach. They will also eat frozen bloodworms and brine shrimp.

Breeding

No actual breed sequence has been documented in an aquarium setting. Although known to be egg-layers, reproduction of rainbow sharks is difficult in an aquarium setting. Large numbers are bred in southeast Asian commercial farms.SeriouslyFish:
Epalzeorhynchos frenatum.
' Retrieved 30 July 2014.

References

External links

* {{DEFAULTSORT:shark, rainbow rainbow shark Taxa named by Henry Weed Fowler rainbow shark