Red tail shark: Size, breeding, lifespan, feeding and tank size

The red tail shark, also known as retail sharkminnow, is a freshwater fish species in the carp family Cyprinidae.

It is endemic to Thailand and is currently critically endangered, but common in aquariums, where it is valued for its deep black body and vivid red or orange tail.

The red-tailed black sharks that are seen today in the aquarium trade are all captive bred.

The Red Tail Shark in any freshwater aquarium may be a standout. 

It is an active fish that is fun to watch and will offer countless hours of fun. 

In this article we cover all you need to know about the Red Tail Shark including: typical behavior, aquarium conditions, dietary needs, ideal tank mates and much more.

You should expect your fish to grow up to 6 inches in captivity, with most growing up to 5 inches, and it should live to about 6 years. 

They should be kept in large aquariums, due to their territorial nature. It’s an omnivore, not a fussy eater, eating most things that are placed in the aquarium.


Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Cypriniformes
Family: Cyprinidae
Genus: Epalzeorhynchos
E. bicolor
Binomial name
Epalzeorhynchos bicolor

Red tail shark Behaviour

You will find your Red Tails fairly timid as juveniles. You should therefore provide them with plenty of hiding spaces (read the section on tank requirements below for more advice). 

They will become territorial as they mature into adults and may be aggressive to fish that stray into their territory. 

Although they do not bite or harass other fish physically they will chase them to the point of exhaustion. 

Day by day, in the bottom section of the tank you will find this fish swimming back and up. You will notice them bullying other fish during their feeding time if you feed them too closely together.

It is possible to keep several bicolor species of Epalzeorhynchos in a very large tank (200 + gallons) with a large number of hide-places but each fish will require at least 1 meter of the length of the tank.


The Red Tail Shark (Epalzeorhynchos Bicolor), also known as Red Tail Black Shark, Fire Tail, Red Tailed Labeo and Red Tail Shark Minnow, is a small freshwater fish originating in Thailand. 

It was found in the clear waters and floodplains of the MeNam Chao Playa basin but it was thought to have become extinct due to excessive poaching.

However the breed lives on in private collections due to the thriving aquarium trade. 

This fish is famous for its impressive looks; it has a black body with a vibrant forked red tail. 

Despite what its name implies, this fish is in fact a type of carp, not a shark and belongs to the family of Cyprinidaes.

Red tail shark Appearance

Red tail shark appearance
Image by Astellar87 from commons wikimedia

The Epalzeorhynchos Bicolor is a standout in any freshwater aquarium, with a red forked tail offset by a deep black body. 

Their dorsal fin is similar in appearance to a shark, which is where their name derives. 

They have long and slim body with flattened sides and curved back. As for their head, you’ll notice it has red eyes and two pairs of barbs are in their mouth. The shape of her mouth helps her scrape algae off the aquarium ‘s bottom. 

You should expect them to grow up to 6 “and grow to about 5.” 

Interestingly when stressed you will notice that their red tail begins to fade in colour.

You will not be able to tell the difference between males and females at birth. However, as the female matures and reaches sexual maturity, you will notice that she has a well-rounded and fatter abdomen. 

The Red Tail Shark is, at last, often confused with the Rainbow Shark. While they both belong to the family Cyprinidae, they are actually separate breeds. The Rainbow Shark also has red fins, as well as the red tail. 

You should also make sure that you do not keep your Epalzeorhynchos Bicolor with Rainbow Sharks as they fight; more on this in the section on compatibility and tank mate.

Red tail shark tank requirement

Since they are known to be territorial (more on this later), you should make sure that juveniles have at least 29 gallons of tank size, and that adults should be placed in at least 55 + gallons. 

You should also try to divide the tank to limit territorial behavior and help protect more shy tank mates. You can use caves, driftwood and ensure that the tank is well planted for splitting the tank up. 

In the aquarium the water conditions should be the following: 

  • Temperature: 72 ° F and 79 ° F respectively.
  • pH: 6.8 to 7.5.
  • Hardness of Water: 5-15 dH.

You should try to ensure the water flows quickly to replicate their natural environment for the water flow. You should use gravel and pebbles for the substrate.

Also bear in mind that they can be jumpers so they should use a weighted lid.

Red tail shark feeding

The Red Tail Shark is an omnivore and its diet will be made up of plants, crustaceans and other small insects in the wild. 

Also known as a scavenger, they will eat most of the things you put into the aquarium including flakes, pellets, live and frozen foods. 

A high-quality pellet or flake should form the cornerstone of their diet. By treating them with meats and plant / vegetables you can add some variety to that.

As for meat type of food you can feed them:

  • Brine shrimp
  • Krill
  • Bloodworms
  • Daphnia

For plant matter and vegetables type you can feed them:

  • Cucumber
  • Peas
  • Zucchini
  • Fruit

If you feed them vegetables make sure they are washed in advance and remove them from the tank quickly to prevent them from rotting. 

They ‘re also known as an algae eater and in your tank you’ll see them scraping algae from the stones. 

Just remember they should have more vegetables and plants than meat, and you should regularly switch your diet to provide them with some variety. 

You may also be considering making your own fish food to ensure they get the best diet possible.

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Red tail tank mates

They have a reputation for being a precarious and rather aggressive fish. This reputation is rightly deserved as it becomes a hostile territorial fish should other fish enter its territory or interrupt its feeding sessions. 

While not necessarily attacking and damaging other fish it will persistently chase them. That may simply cause the bullied fish to die of exhaustion and malnutrition. 

Even though the Red Tail is not exactly the ideal candidate for a community tank, with other fish you can still keep it. You just need to watch your selection carefully.

Ideal tank mates should be robust, quick and tend to spend their time in the middle and upper water column levels. A couple of examples include: 

  • Bala Shark
  • Barbs
  • Danios
  • Angelfish
  • Gouramis
  • Tetras (emperor, cardinal, neon and glowlight)

As for avoiding fish, the list is exhaustive! 

We should avoid other sharks such as Rainbow and Red-finned. It is also possible to bully fish with significant red color.

I would also recommend avoiding all other bottom dwellers including Plecos and Cichlids simply to be safe. 

Lastly, it goes without saying that any peaceful / docile fish should be avoided too.

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Red tail shark breeding

Their abdomen becomes fatter and more rounded when the females are ready to reproduce; this is the only visual difference between a male and a female. 

If you plan to breed them in your aquarium at home we have some bad news. It’s virtually unheard of that anyone in a home aquarium has successfully bred Red Tails.

This is mainly due to how intolerant they are towards one another. 

As mentioned earlier, they ‘re all but extinct in the wild, so keeping them from extinction is left to large commercial breeding establishments.

Hormones are utilized in such commercial environments to induce mating.

Since the Red Tail is a layer of eggs it tends to spawn in rocky caves. Once the male fertilizes the eggs it will take the fry to hatch between 40-60 hours.

As the fry develops, the color changes from silver to a silver / brown color before finally black. Its red tail will develop around 10 weeks of age.

Holding Red Tail Sharks alongside other Red Tail Sharks 

You will know, if you’re read above, that the Red Tail Sharks are extremely territorial. For this reason we wouldn’t recommend keeping more than one in a tank if you’re a startner. 

However, if you insist that more than one be kept in your aquarium then do so with caution. 

Make sure you have a large aquarium; you need to add a minimum of 1 meter to the tank for each Red Tail that you add. You’ll also have to keep at least 5 sharks at once.

This prevents an excessive bullying of a single fish to death by the “alpha.” 

A tank of this size is unrealistic for most fish enthusiasts therefore why we advise to keep them singularly.

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Female Red Tail Shark The Red Tail Black Shark is native to Thailand ‘s freshwater algae ponds as mentioned earlier. They will inhabit the bottom lands, streams and woodland during the rainy season. 

It is a very active fish that will “busy” most of its time 

Due to industrial grade agriculture and excessive poaching, the wild population of Red Tails has been all but eliminated over the last few decades. Now it is listed as being critically endangered. 

A flourishing aquarium trade has, however, meant that this breed still exists. 


The species is endemic to Thailand and was described by Hugh M. Smith in 1931 as ‘not uncommon’ in Bueng Boraphet and the streams that lead from it, and as being found as far south as Bangkok in the Chao Phraya River.

A 1934 expedition reported a specimen being caught in the Silom Canal.

It is known only at a single location in the Chao Phraya basin as of 2011 and has a critically endangered status on the IUCN Red List.

It was thought to be extinct in the wild from 1996 until 2011.There is no evidence that collection is responsible for the decline of the species for the aquarium trade, and it is more likely that the building of dams and the draining of swamps that took place during the 1970s was to blame.

How long does a red tail shark get?

Red tail shark fish usually grows up to 6 “and grow to about 5.” 

Red tail shark fish tank temperature

The ideal tank temperature for red tail shark fish within the water should be maintained around 72 ° F and 79 ° F respectively.

Is the Shark Red Tail Right For Your Aquarium? 

The ideal tank temperature for red tail shark is around 72 ° F and 79 ° F respectively.

Concluding Thoughts

We hope this full Red Tail Sharks guide has helped you decide whether or not they’re the right fish for your aquarium. 

While they are an entertaining and beautiful fish, beginner fish keepers are faced with several challenges; most notably their territorial nature and great aquarium requirements. 

However, by using plenty of hiding places in a large tank, if you have the space and budget for such an aquarium many of their territorial behavioral traits can be avoided. 

If you can provide them with an appropriate aquarium, they make a fantastic addition to your tank, giving you rich vibrant colors.

You may contact us for suggestions and feedback. We at Planet fish value your suggestions.

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