Red-Tailed Black Shark (Epalzeorhynchos bicolor)

Common Name:

Red-Tailed Black Shark.

Scientific Name:

Epalzeorhynchos bicolor.

Other Names:

Red-Tailed Shark, Red-Tailed Sharkminnow, Red-Tailed Black Sharkminnow.

Family:

Cyprinidae.

Distribution:

This used to be found throughout Thailand, especially in the Chao Phraya and Mekong Basins, but they no longer exist in the wild.

Size:

Approx 6 inches or 15cm .

Diet:

They are omnivorous, so they should be fed greens along with the standard aquarium fare. They have underslung mouths, so sinking tablets and pellets will be appreciated, as will blanched greens.

Water Temperature:

72 to 80 degrees Fahrenheit (22 to 26 degrees Celsius).

Water Chemistry:

They can deal well with medium to hard water and will take well to somewhat soft water, too.

pH:

Slightly alkaline water (7-7.4) is best for these fish, but they can deal well with a wider ranger.

Life Span:

6-10 years.

Description:

These are moderately large fish with streamlined bodies that indicate their former presence in fast-flowing rivers (along the bottom, natch). They have underslung mouths as well. The fish should be a deep black with red fins, but they are often found in a faded state. Good water quality and a few hiding places will color them happy, and a happy-colored Epalzeorhynchos bicolor is beautiful!

Species Behaviour:

These can be nasty fish, and probably should not be kept with conspecifics in any aquarium smaller than 55-75 gallons. They will keep to themselves (mostly) when they are given many hiding spaces. They often swim up and down in front of the aquarium glass and are valued members of the community tank because of that behavior. Less-tough bottom-dwellers are at risk. The RTBS may pester shy fish to the point where they succumb to the stress.

Happy E. bicolors tend to have the coloration that make these so valued within the hobby.

Sexing:

They are essentially isomorphic. Some differences in ventral coloration (black for males, lighter for females) and fin shape (rounded tips for the females) have been cited, but these are standard guesses for Cyprinidae, and have not been verified over a large sample. These may be proven to be correct in the future, but they should be regarded as unproven and taken with a grain of aquarium-ready salt.

Breeding:

Very, very rarely will E. bicolor breed in aquaria. It has not been well-documented if it has, in fact, occurred. Those specimens that are found in the hobby are usually bred in ponds in Thailand. Often, hormonal treatments are used to induce spawning.

Water Quality:

They need soft water, but might be able to adjust to hard water through drip acclimation. Smith recommends dH levels under 5. A pH 5.5 to 8.5 is all right for long term maintenance, but anything outside of 6-7 also requires drip acclimation.

Natural Conditions:

These aren't found in the wild, but they used to be found in fast-flowing rivers.

Minimum recommended tank size:

40 gallons.

Tank levels:

Bottom feeder.

Miscellaneous:

These are now extinct in the wild and no intensive program to restock the Chao Phrayo (and possibly the Mekong) with them are currently underway.

They are often bred by hormonal treatment. Hormone injections are rarely given to fish destined for the fish tank, though, because even these will not color up a less-than-happy E. bicolor.

It was only recently that E. bicolor became the preferred name for the Red-Tailed Black Shark. Many aquarium books and resources will refer to the RTBS as Labeo bicolor.

Photo Credit:

Photo supplied courtesy and ^©BlueLagoon.