Red Tail Shark: Tankmates, Care Guide and More…

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

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

Due to their non-fussy nature, they are very easy to feed, and once settled into their aquarium shouldn’t offer too many difficulties to keep happy.

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

Let’s start with a quick summary table before we move on to discuss their recommended tank mates and care requirements.

Learn Even More: Download our free Red Tail Shark guide to get more information about this fish and their dietary needs and habitat.

Red Tail Shark Facts & Overview

Red Tail Swimming

Care Level:Moderate
Color Form: Black, red
Lifespan:5-6 years
Size:Up to 6 inches
Diet: Omnivore
Family: Cyprinidae
Minimum Tank Size:55 gallons
Tank Set-Up: Tropical freshwater: rocks, caves and plants
Compatibility: Moderate

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 native to Thailand.

It was found in the clear waters and floodplains in the MeNam Chao Playa basin, however due to excessive poaching it was thought to have become extinct. However, due to the thriving aquarium trade the breed lives on in private collections.

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

Despite what its name would imply, this fish is in-fact a type of carp, not a shark, and belongs to the Cyprinidae family.

In captivity you should expect your fish to grow up to 6 inches with most growing to 5 inches, and it should live to around 6 years old.

Due to its territorial nature they should be kept in large aquariums. It is an omnivore and not a fussy eater, eating most things placed into the aquarium.

Typical Behavior

As juveniles you will find your Red Tails to be fairly timid. For this reason you should provide them with plenty of spaces to hide (read the tank requirements section below for more advice).

As they mature into adults they will become territorial and can be aggressive to fish which stray into their territory.

Whilst they won’t physically bite or harass other fish they will chase them to the point of exhaustion.

Day to day you will find this fish swimming back and to in the bottom section of the tank. During feeding time you will notice them bullying other fish if you feed them too closely together.

In a very large tank (200+ gallons) with large number of hide-places it’s possible to keep several Epalzeorhynchos bicolor species, however each fish will require at least 1 meter of the tank length.


Red Tail SharkThe Epalzeorhynchos Bicolor is a standout in any freshwater aquarium, with a deep black body offset with a red forked tail.

It’s their dorsal fin that is similar in appearance to a shark, which is where its name comes from.

Their body is long and slim with flattened sides and a curved back.  As for their head, you will notice it has red eyes, and its mouth has two pairs of barbs. The shape of its’ mouth helps it to scrap algae off the bottom of the aquarium.

You should expect them to grow up to 6” with most growing to around 5”.

Interestingly when they are stressed you will notice their red tail starts to fade in color.

At birth you won’t be able to tell the difference between male and females. However, as the female matures and reaches sexual maturity, you will notice she has a fatter and well-rounded abdomen.

Finally, the Red Tail Shark is often confused with the Rainbow Shark. Whilst they do both belong to the Cyprinidae family, they are in fact separate breeds.  In addition to the red tail, the Rainbow Shark also has red fins.

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

Habitat and Tank Requirements

Female Red Tail SharkAs previously mentioned the Red Tail Black Shark is native to the freshwater algae ponds of Thailand. During rainy season they will inhabit the bottom lands, streams, and forest area.

It is a very active fish that will spend the majority of its time “busy”.

Over the last few decades the wild population of Red Tails has been all but eliminated due to industrial grade farming and excessive poaching. It is now listed as critically endangered.

However, a thriving aquarium trade has meant this breed is still in existence.

Tank Conditions

As they are known for being territorial (more on this later), you should ensure that juveniles have a tank sized at least 29 gallons and adults should be placed in at least 55+ gallons.

You should also try to split the tank up to limit the amount of territorial behavior and help protect more timid tank mates. To split the tank up you can use caves, driftwood and ensure the tank is well planted.

Water conditions in the aquarium should be as follows:

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

For the water flow you should try to make sure the water is fast flowing to replicate their natural environment. For the substrate you should be using gravel and pebbles.

Also, bear in mind they can be jumpers so a weighted lid should be used.


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

They are also known for being a scavenger and as a result will eat most things you put into the aquarium including flakes, pellets, live and frozen foods.

The cornerstone of their diet should be comprised of a high quality pellet or flake. You can add some variety to this by treating them with meats and plant/vegetables.

As for meat you can feed them:

  • Brine shrimp
  • Krill
  • Bloodworms
  • Daphnia

For plant matter and vegetables you can feed them:

  • Cucumber
  • Peas
  • Zucchini
  • Fruit

If you are feeding them vegetables make sure to wash them beforehand and quickly remove them from the tank to prevent them rotting.

They are also known as an algae eater, and you will see them scraping algae from stones in your tank.

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

You might also consider making your own fish food to ensure they are getting the best possible diet.

Compatibility and Tankmates

Red Tail ApperanceThey have a reputation for being a somewhat aggressive and precarious fish. This reputation is rightly deserved as it a territorial fish that will become hostile should other fish enter its territory or interrupt its feeding sessions.

Whilst it won’t necessarily attack and damage other fish it will chase them persistently. This can cause the bullied fish to simply die of exhaustion and malnutrition.

Even though the Red Tail isn’t exactly the ideal candidate for a community tank, you can still keep it with other fish. You just need to be careful with your selection.

Ideal Tankmates should be robust, fast, and tend to spend their time in the middle and upper levels of the water column. A few examples include:

As for fish to avoid, the list is extensive!

Other sharks such as Rainbow and Red-finned should be avoided. Fish with significant red coloration can also be bullied. To be safe I would also recommend simply avoiding all other bottom dwellers including Plecos and Cichlids.

Finally, it goes without saying any peaceful/docile fish should also be avoided.

Keeping Red Tail Sharks with other Red Tail Sharks

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

However, if you are insistent on keeping more than one in your aquarium then do so with caution.

Make sure you have a large aquarium; for each Red Tail you add, you need to add a minimum of 1 meter to the tank. You will also need to keep at least five sharks at once. This prevents the “alpha” from excessively bullying a single fish to death.

For most fish enthusiast, a tank of this size is unrealistic hence why we advise keeping them singularly.


When the females are ready to reproduce, their abdomen turns fatter and more rounded; this is the only visual difference between a male and a female.

If you’re planning to breed them in your home aquarium we have some bad news. It is practically unheard of that anyone has successful bred Red Tails in a home aquarium. This is mainly because of how intolerant of each other they are.

As previously mentioned, they are all but extinct in the wild, so it’s left to large commercial breeding facilities to keep them from extinction. In such commercial environments hormones are used to induce mating.

As the Red Tail is an egg layer, it tends to spawn in rocky caves. Once the male fertilizes the eggs, it takes between 40-60 hours for the fry to hatch. As the fry develop they will change in color from silver, to a silver/brown color before finally completely black. At around 10 weeks of age their red tail will develop.

Is the Red Tail Shark Right For Your Aquarium?

We hope this complete guide to Red Tail Sharks has helped you decided whether they are the right fish for your aquarium or not.

Whilst they are an entertaining and beautiful fish they do present several challenges to beginner fish keepers; most notably their territorial nature and large aquarium requirements.

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

If you can provide them with a suitable aquarium they will make a fantastic addition to your tank, providing you with rich vibrant colors.

Let us know in the comments section below your experiences with Red Tail Sharks…

About Robert 394 Articles
Robert Woods is the creator of FishKeeping World, a third-generation fish keeper, and a graduate in animal welfare and behavior. He is also a proud member of the Association of Zoos and Aquariums, the Marine Aquarium Societies of North America, and the Nature Conservancy.


  1. Ej says:

    This helped me so much. I have 2 10cm red tails in my 60 liter aquarium, im gonna go put them in my 160 liter aquarium instead then.

  2. Paula says:

    My red tailed shark looks sick, on its left side it looks like a big Tumor ! RIgbo side is normal! Is it dying?

    • Fishkeeping World says:

      Hi Paula, sorry to hear this! I think your best bet would be to get a fish veterinarian to take a look. Let me know how you get on. Thanks, Robert

  3. Deborah Panza says:

    I have a 125g tank with silver dollars,tiger Barb’s,danios, cichlids,Cory catfish, African cichlids, an upside down catfish, irridescent shark,pleco, and Columbian pictus catfish, and wanting to add my redfinned shark in with them. Does anyone know if these tankmates are compatible with this shark? Even though I have an irridescent shark. Most fish are similar size except silver dollars and cichlids.

    • Aaron L Putnam says:

      I have one with my tiger Barb’s 2 rapheal cats electric blue acara large sail fin pleco 4 Chinese algea eaters.

  4. Michael Kenney says:

    I have a red tail black shark in a community tank. My tank is a 30 gal long and I have about 5 large rocks (35lbs) at one end. Have had the shark since it was about 6cm and it is now about 12 cm long. He is a big sissy and afraid of his shadow.. or is it my shadow. Most active when lighting is low. He has claimed the pile of rocks as his territory and will chase away any Panda Corys or Julii Corys that come inside. He is not very aggressive towards the Espi Rasboras or the Tetras at all. He is the largest fish in the tank and a great show piece.

  5. Steve says:

    I have a 20 gallon tank and I would love to have 2 sharks I have a red tail a few days only but looking to put in another sharks now which sharks can I place with the red tail

    • Fishkeeping World says:

      Hi Steve, any sharks you add will need to be robust and fast. Another shark you could include is the Bala Shark. Thanks, Robert

    • Anthony says:

      Steve a 20g tank is small for one red tail. I would NOT advise adding ANY other shark. I also would NOT get a bala shark unless you have a 150g or bigger. Please do not add any sharks to a 20g tank. I would advise a community tank with nothing bigger than some barbs. Other fish in similar size to barbs or smaller. Maybe a bristle nose pleco for the bottom (do NOT get a common pleco)

  6. Cat says:

    I have four guppies I thought that they would swim all over my tank but of course they stay at the top I want to get a rainbow shark I had two but they both died I love how they look and how they swim at the bottom of the tank but can I get another one and put them in my tank with my guppies. I don’t want to stress any of my fish out.

    • Fishkeeping World says:

      Hi Cat, Guppies are quite a peaceful fish so I’d avoid housing them with Red Tail Sharks. You might want to add Danios or Tetras to the tank with Red Tail Sharks instead. Thanks, Robert.

  7. Terry says:

    I’ve had a red tail for several years,band he is an anti-social grumpy pants. He never comes out of his stump, at least not when anyone is awake! I suppose he comes out at night to eat…the only part of him we ever see is his red tail sticking out of the stump.

  8. Mike says:

    Hi, I am in the process of seting up a freshwater planted tank. It will be 2m long x 70cm wide x 50cm tall. And I can’t decide what fish to put in it. First I thought to put a ton of guppies but I can’t get them all to be the same color so that option is discarded. Now the candidates are:
    -Red tails are my favourites and would like to ad 5 (at least).
    -Zebra plecos (Just read 🙁 not compatible with red tails).
    -Bala sharks
    -Clown loaches

    Can you please tell me in that tank which would be compatible, and how many should I house at a time? In what order should they be introduced to avoid fights. Thanks for taking the time to put up so much info, this site is amazing!!!

    • Fishkeeping World says:

      Hi Mike, Thanks so much for the great feedback. You’d be better served looking at one of the online aquarium stocking calculators. They’ll give you a good idea of which fish are compatible and how many you can keep in your tank. Thanks, Robert.

  9. Joan C. says:

    Just bought two silver red tailed sharks yesterday. Today they were chasing each other, batting heads and trying to bite each
    other mouth to mouth. Is this Normal behavior? Its been a long time since I had a tank and am just getting back into the
    hobby. Ive had kuli loaches, places, Cory catfish, betas, guppies, in the past. I also have an outside pond with goldfish
    and KOI – the German ones.

    • Fishkeeping World says:

      Hi Joan, you should only keep one of these per tank as they are extremely territorial. If you are keeping them in one tank, you’ll need a much larger tank with plenty of hiding places. Thanks, Robert

  10. Liz says:

    I have a redtail and a rainbow shark so far so good..i also have plecos and cichlids which I read are not compatible…I have a big tank (125g) and lots of hiding spots…and i have been keeping an eye. What behavior should i watch for to indicate i need to separate?

    • Fishkeeping World says:

      Hi Liz, any signs of aggression, or fighting. Equally watch out for any fish which are being more shy than usual, not eating etc. Many thanks, Robert

  11. kim Castro says:

    When does the shark reach full size?

    • Fishkeeping World says:

      Hi Kim, it really depends on the individual fish but it usually takes around 1 year for these fish to grow to around 4 inches long. Thanks, Robert

      • Karen says:

        I have a red tailed shark he’s over 4 years old now he lives in a 125 litre tank with a super red bristlenose who I’ve had for 4 years as well as 8 rummy nose tetras ,3 neon tetras and 1 bronze cory .. prev had 4 corys but they’ve now sadly passed one by one after many years .. the tank has always been peaceful , I’m looking to restock some corys would I be able to have another type or should I stay with bronzes ? Plus could I up the number of neons as these were given me many years ago ? I run a huge outside filter as well as well as good sized inside filter & often do water changes so wondering if could add back to tank and what with thanks ?

  12. Gabrielle Gabriel says:

    Can i put angel fish with my red tail shark? if so how many should i purches?

  13. Millie says:

    Hi do I put my shark in first if I am going to add more fish or do I add the fish then shark at a later date ?

  14. Ken Taylor says:

    I have a red tailed black shark in my tank with other community fish and a catfish. I’ve had no problems until recently when I’ve lost several guppy’s and neons. When I say lost I mean lost, there are no signs of them. Any idea what’s happening to them?

  15. Fishlover says:

    Why Algae eaters can I put with my red tail

  16. Chase says:

    I have a red tail and I was wondering what other fish I could have with it
    right now I have 3 tetras,2 angel fish and my red tail.

    Also, could I put dalmatian moleys with my red tail?

  17. Dr.D.Saravanan says:

    Hello Mr.Kim,
    I have two red tailed and red finned shark. It is in my 2 feet by 2 feet aquarium and was good these days after changing the water in the tank and kept a new toy where it had good place for hiding. As it did not come for eating I removed the toy. Now it becomes more scary and always stay beneath the tank on the stones. When any fish touches or little sound comes it hits itself on the glass wall or on the rocks. It has its food rarely. What to do? I am little worried about, as it seems dying. It shows sometimes unusual behaviour by falling from top water to bottom as dead body and lays upside down for some 2 to 3 minutes and then again becomes little normal and continues its bottom living. I need your advice to recover him.

  18. Robert cairns says:

    Are Cory’s alright to keep with red tail sharks and if so how many sharks go together or just get one

  19. Tom says:

    Kept 2 rainbow shark in a community tank years ago, chased each other about, then one day they came out and displayed to each other after that on regular thing.

  20. Matthew says:

    Hi I just bought a red tail and he’s a little scared of everything and I got a bigger tank 10 gallons and it needs to set so I have him in a 1 gal is that ok

  21. Kelli says:

    I have a red fin shark. It’s in a 50 gallon tank with 5 tetras and 1 other bottom fish i don’t know what it is. This red fin shark I have had for about 9 years.

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