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

/The Conscientious Aquarist

 The Redtail Black Shark, Epalzeorhynchos bicolor formerly Labeo bicolor

By Bob Fenner

Epalzeorhynchos bicolor

A perennial favorite, the Redtail or Redtail Black Shark, Epalzeorhynchus bicolor (don't try saying this fast out loud with a mouth full of chips!) is a largely likeable minnow (family Cyprinidae) that does well in a fairly wide range of water conditions and tankmate mixes. However, like all species, its use does have limitations. This fish can grow quite large and become feisty with its own and too-easy-going fishes... particularly ones with long fins and slow movements. Placed with medium temperament and/or fast fishes this problem is solved but for one last common difficulty with most minnow-sharks: Their penchant for launching themselves out of their tanks. This is also easily solved by making sure you have a complete cover over the system. Other than some mix of green and meaty foods and regular water changes, Redtail (black) sharks are a gorgeous addition to medium-aggressive freshwater fish tanks.

Epalzeorhynchos bicolor (Smith 1931), the Redtail Sharkminnow to science was Labeo bicolor, the Red Tail shark to the aquarium hobby.  Found originally in Thailand. Grows to a bit under five inches in length (if it doesn't jump out first). Cond.s: pH 6.5-7.5, dH to 15, temp. 22-26 C.  There are mutations of this species including albino.



    Distinctively velvet-black bodied (with a distinct black spot on the upper forward flank) and variably red (depending on upbringing, mood, health...) caudal/tail fin.


    Can be a bully with age, growth. Fishbase.org calls out for a 120 cm. long system as a minimum... to alleviate such aggression. Otherwise, a generally reclusive to the point of shyness species that inhabits darker, corners and nooks in most settings.


    As stated, a developing bully of sorts that is best kept/displayed as juveniles in crowded settings with members of its own kind and kept one to a tank by aquarists. In larger, well-established planted tanks... with other medium-aggressive fishes, and/or fast, smart types like larger Danios and Barbs. Should not be housed with Bettas, Angelfishes, others with long, flowing finnage.


    A good number of this minnow-shark are lost just after arrival due to cumulative stress. It cannot be emphasized enough to show patience here... to wait several days to weeks after a shipment to assure sufficient rest time before yet moving specimens again. Look for signs of intra-specific aggression. See pic at right re the upper fish's split dorsal fin. You want to buy the "winner" in such aggregations. The likely larger individual with less to no split fins or bloody body markings (pay particular attention at the areas where fins are attached). The winner will be likely out front and center, with the subdominant fishes hiding in the corners.


    The bigger the better. Four foot across systems are a good start, though I've seen happy specimens in 30, 36 inch wide tanks. Subdued lighting, live plants are best, though plastic can be made to work. Water of moderate pH, hardness and temperature is fine.


    Redtail black minnow-sharks will consume most all types of foods, prepared, fresh and frozen/defrosted. Some of all are best to offer, with a bit of greenery offered daily. This latter can be pellets or specialized wafers or frozen cubes, but is best supplied in a ready, growing plant mass in their system. As you will find, the Bicolor shark-minnow feeds almost continuously during light hours, and having something of low food value about discounts much anomalous behavior.


    Epalzeorhynchos bicolor is a fine-scaled minnow/toothed carp... and like all others of its family is susceptible to the usual parasitic scourges of freshwater tropicals. Ich and velvet are easily caught by this species, and thankfully just as easily cured (if discovered, treated quickly). Half doses of dyes like Malachite Green and elevated temperature (to the mid 80's F.) are best for most such complaints.


    This species has spawned in captivity and is produced as well as live-collected (in Thailand) for the ornamental trade.


    The Redtail/ed Black Shark is a standard offering in the western pet-fish interest. Though it can be a "stinker" in terms of aggression to small, slow, long-finned fish tankmates, it has redeeming qualities of beauty, grace and easy-feeding to recommend it. Just take care to keep it fed (best with live plants present) and keep your aquarium top covered... as this is one of the most notorious "jumpers" in the aquarium hobby.

Bibliography/Further Reading:

Axelrod, Herbert R. Labeo bicolor, the Red-Tailed Black Shark. TFH 1/59.

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.

Tavares, Iggy. 1999. The Red-Tailed Shark. FAMA 5/99.

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