|Rainbow shark, red-finned shark, ruby shark|
The rainbow shark (Epalzeorhynchos frenatum) is a species of Southeast Asian freshwater fish from the Cyprinidae family. It is a popular, semi-aggressive aquarium fish. It is also variously known as the ruby shark, red-fin shark, red-finned shark, rainbow sharkminnow, green fringelip labeo, whitefin shark and whitetail sharkminnow. Unlike true sharks, which belong to the Chondrichthyes ("cartilagenous fishes") lineage, the rainbow shark is an actinopterygiian ("ray-finned fish").
The rainbow shark has an elongated, dark black or dark blue body, or a bright blue body. It also occur in an albino variety, with a white body and bright-orange fins, or a light orange body with dark-red fins.  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 6 in (15 cm) long with an average life span ranging from 4 to 6 years.
Distribution and habitat
In the aquarium
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, especially in confined environments like aquaria. It may also increase the risk of the fish jumping out of its tank. This makes breeding difficult. 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. 
An adult rainbow shark thrives in a 55-gallon (minimum 30-gal) tank with water at the neutral pH range (6.5 to 7.0 pH), with temperatures between 22 and 26 °C (72 and 79 °F), and water hardness maintained at 2 to 15 dH. They must have this much space, as they frequently swim around quickly and will terrorize other fish in any tank under this size.
Rainbow sharks are also compatible with barbs and rainbowfish, which are upper- and middle-tank dwellers. They can also live with danios, loaches, plecos, rasboras, and gouramis. They are not compatible with smaller, more timid fish in the tank, as the sharks may chase terrorize them by chasing them out of his/her territory. 
Rainbow sharks are not picky herbivorous and omnivorous eaters, but are primarily consumers of algae in the form of tablets, wafers and flakes. They also eat live foods, such as insect larvae, tubifex worms, periphyton, crustaceans, phytoplankton, zooplankton and aquatic insects. Diet also include lettuce and spinach. They will also eat frozen bloodworms and brine shrimp.
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.
The albino red-fin shark or albino rainbow sharkminnow is a variety of rainbow shark with a white body and red/orange fins. It closely resembles "normal" rainbow sharks in temperament and appearance, thus they share the same common names in the aquarium industry. These have sometimes been referred to as E. munense, but this is a separate species that rarely enters the aquarium trade.
|Wikimedia Commons has media related to Epalzeorhynchos frenatum.|
- Vidthayanon, C. (2012). "Epalzeorhynchos frenatum". IUCN Red List of Threatened Species. Version 2014.1. International Union for Conservation of Nature.
- Froese, Rainer and Pauly, Daniel, eds. (2014). "Epalzeorhynchos frenatum" in FishBase. April 2014 version.
- Red-fin Shark, Rainbow Shark, Ruby Shark (Epalzeorhynchus frenatus), Mongabay.com, 2006, retrieved on August 17, 2007
- Rainbow Shark (Epalzeorhynchos frenatum, Fowler, 1934), AquariaCentral.com (undated), retrieved on August 17, 2007
- Rainbow Shark (Epalzeorhynchos frenatum), AquariumLife.net (undated), retrieved on August 17, 2007
- Rainbow Shark Information, TimsTropicals.com, 2007, retrieved on August 17, 2007
- Michael Andrew Abernathy (2004). Effects of Water Hardness on the Survival of Rainbow Sharkminnow (Epalzeorhynchos frenatum) Eggs and Larvae (PDF) (Master of Science thesis). University of Florida. Retrieved August 17, 2007.
- SeriouslyFish: Epalzeorhynchos frenatum. Retrieved 30 July 2014.
- 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
- Evans, Sean. The Tropical Tank: Red Finned Shark, TheTropicalTank.co.uk, 2007, retrieved on August 17, 2007
- SeriouslyFish: Epalzeorhynchos munense. Retrieved 30 July 2014.
- Froese, Rainer and Pauly, Daniel, eds. (2014). "Epalzeorhynchos munense" in FishBase. April 2014 version.