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Related Articles: Cyprinids/MinnowsMinnow "Sharks", Bala or Tri-Colored Sharks, Redtail Sharks, Black Sharks,

/The Conscientious Aquarist

 The Rainbow, Redfin and Albino Minnow Sharks, Epalzeorhynchos munense & E. frenatum

By Bob Fenner

Epalzeorhynchos  frenatus

    These two species of minnow sharks, Epalzeorhynchos munense and frenatum are unfortunately cross-named in aquarium stores, and unless you have both in hand, can be very difficult to discern one from the other. Fortunately they are similar in temperament (aggressive with age/growth) and about the same size (E. munense grows to some 9.3 inches, E. frenatum to some 15 cm., but both are rarely more than 3-4 inches long in captivity.

Epalzeorhynchos munense (Smith 1934), sold interchangeably with E. frenatum as the Rainbow and Albino Shark or Red-Finned Shark/minnow  in the aquarium trade, though strictly speaking the former and latter scientific and common names are linked. Differentiable by position of dorsal and pelvic finnage. The dorsal base starts ahead of the pelvic fins in E. munense (far right), just about at it in E. frenatus (at left). http://fishbase.sinica.edu.tw/Summary/species Summary.phpID=12069&genusname=Epalzeorhynchos& speciesname=frenatum http://fishbase.sinica.edu.tw/Summary /speciesSummary.phpID=27163&genusname= Epalzeorhynchos&speciesname=munense


The dorsal base starts ahead of the pelvic fins in E. munense (far right).


    Both species are antagonistic toward their own kind, and other similar-appearing fishes. They are best kept one to a tank, unless the system is very large (hundreds of gallons). Small individuals can be, and often are crowded in retail and wholesale settings... with "winners" occupying choice settings, and less dominant individuals beaten into corners.


    When small, these minnow sharks with red fins can be housed with most all other peaceful freshwater tropicals. With increasing size though, they tend toward territoriality and are best kept with other medium aggressive fishes, the best of best, with types of life they're naturally found with... larger gouramis, barbs, danios and S. E. Asian catfishes of various species. Though they're easier-going than other species of minnow-sharks these two are best not mixed with others of their own kind or similar appearing "sharky" cyprinids.


    Of good specimens is easily done, with a few caveats. Beware of "just arrived" shipments, as "anomalous wipe-outs" of such are not uncommon. Small specimens (less than an inch or so) in particular sometimes "just die" due to starvation, accumulated stress. Hold off for a week or more after they've been at your store before bringing them home. Color of individuals is variable and generally much lighter the smaller the fish are. This is not a good criterion to select/de-select by. Torn fins do heal, but it is best to select "winners", leaving sub-dominant fish at the store to recuperate.


    A tank of good size, at least forty gallons for a single adult individual, with driftwood, live plants... is ideal. Subdued lighting, water of moderate pH (6.8-7.5) and hardness, steady temperature and a minimum of nitrogenous waste (less than 10 ppm of nitrate, no ammonia or nitrite) is best. Additionally, these fishes require water of good circulation and high dissolved oxygen content.


    Rainbow and Red-Fin Sharks are largely herbivorous, eating good amounts of algae and vascular aquatic plants in the wild, grinding these coarse foods with their pharyngeal teeth (they lack "jaws" teeth). They need these foods to be supplied in captivity, along with some meaty material daily. Greens can be provided in a few formats, pellets, wafers, sheets... but are best proffered through the growing of live plants in their system.


    These minnow sharks are generally disease resistant, though they show a medium susceptibility to ich/whitespot disease. This parasite, if detected early, is easily cured with half dosages of Malachite Green solution and elevated temperature.


    These species are produced through gonadotropic hormone injection. Like most minnows, they are egg scatterers, and egg-eaters. Adults are removed after distributing a few to several hundred eggs and milt. These fertilized eggs hatch out in about a day at 80 F. and are free-swimming in another day. Fry are reared on Artemia and finely divided prepared foods.


    Coming in albino and even long-finned variants these members of the genus Epalzeorhynchos have similar needs and temperaments to their fellow famous congeners, the Redtail Black Shark and Flying Fox/es. Give them room, some greenery and a secure top... keep them (best in a biotopic presentation) with similarly profiled species, and you will have a sturdy center piece specimen.

Bibliography/Further Reading:

Cochran, Gary. 2001. No jaws here. Two aquarium sharks (RT and RF) . TFH 8/01

Edmonds, Les. 1996. Freshwater "Sharks". TFH 11/96.

Hunziker, Ray. 1992. The Sharks that aren't. TFH 4/92.

Taylor, Edward C. 1991. Freshwater Sharks- the 'name game'. Pets, Supplies, Marketing 11/91.

Vajdak, Bohumil. 1986. Spawning Labeo frenatus. TFH 10/86.

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