Red Tailed Shark

The red tail shark is a member of the Cyprinidae family of freshwater tropical fish. The red tailed black shark falls into the same family as carp and minnows. Contrary to the name, the red tailed shark is actually not a shark. The “shark” name came from the dorsal fin this freshwater tropical fish possesses resembling an actual shark.

Common Name/Origin: The red tail shark is also known as labeo bicolor, fire tail, red tailed black shark, and epalzeorhynchus bicolor. This Cyprinidae originates from the streams and waterways of Thailand.

Size: The red tailed shark averages 6 inches in length.

Temperament: The red tailed black shark can be an aggressive fish. This fish often fights or harasses other red tail sharks. It is highly recommened to house only one of this species unless you have a very large tank. The red-tailed-shark should not be kept with extremely docile or peaceful fish. The red tail shark is a territorial fish that will chase other fish away from their territory or become aggressive during feeding. Some fish-keepers have had great luck with their red tail shark, so it all depends on the individual fish.

Sexing: This species is extremely hard to sex. Female epalzeorhynchus bicolor sharks are usually larger than the males. The female will have a full, wide stomach and the males will be more slender.

Tank: The aquarium tank recommended to keep the red-tail shark is at least 20-gallons. The tanks should be decorated with several places for this fish to hide. The red tail shark will enjoy a well planted tank with caves or driftwood for shelter. The tank should have a tight fitting lid because this freshwater tropical fish species is known to jump out of tanks.


pH: 6.5-7.6

Soft-Medium Water

Temperature 72-80 °F

Feeding: The red tailed black shark is an omnivore scavenger. This freshwater tropical fish will eat just about anything that you put into the tank. Like any other fish I keep, I recommend a very high quality pellet or flake food and supplement with brine shrimp, mysis shrimp, small krill, or bloodworms. Like any other freshwater tropical fish, please mix up their diet on a regular basis.

Behavior: As mentioned above, the red tailed black shark can be territorial and chase other fish around the tank. This species of freshwater tropical fish swim back and forth, mainly on the bottom of the tank searching for food. When you feed the tank, you will notice the redtail shark chasing other fish away from the food.

Tankmates: It is highly recommended to keep only one labeo bicolor per tank. Depending on each individual fish, most redtail sharks will harass smaller, more peaceful fish. Many cichlid keepers keep redtail sharks in their tank because they can hold their own with some more aggressive fish. Do not keep red tail black sharks with other bottom dwelling fish such as cory cats. They will compete for the same territory and food.

Key Features: The redtail shark will cruise near the bottom to mid-level of the aquarium tank. This fish is an active fish and is constantly on the move searching for food. The unique look and shape of this fish is what many fish-keepers love. The shark-like dorsal fin and beautiful red tail contrasted with the black body makes this fish very appealing.

Breeding: The red-tailed shark is extremely hard to breed in the home tropical fish aquarium. Most specimens purchased in our local fish stores are bred in commerical fish farms in Thailand. The red-tail shark is an egg layer.

Summary: If this popular freshwater tropical fish is on your list of fish to purchase, please just purchase one of this species unless you have a huge tank. This Cyprinidae is known to be a chaser and will harass other tropical fish in your tank. This specimen often does well with more aggressive fish such as cichlids. Remember to keep a tight lid on your aquarium tank because the epalzeorhynchus bicolor is a jumper!

104 thoughts on “Red Tailed Shark”

    1. if you have a 45 gallon taank then no but not having a 45 gallon the shark will kill the guppie

  1. Hi I have rts it’s about a year old have just discovered tonight that it has eat one of my Angel fish and is acting very agresive towards other fish never had any problem with it until now any suggestions?

    1. He’s probably starting to settle down in the tank and so is now starting to mark out his territory (or grumpy old man syndrome as I like to think of it). If its aggressive now it’ll probably only get worse unfortunately. While there are many comments of people saying their red tail is fine. There’s also many where they’re not fine, sounds like you got a not fine one. Nothing much you can do unfortunately either get rid of it or get rid of the other fish or get a massive tank so there’s plenty of room for them not to argue.

      1. My rts I’ve had for 18 years. I know mine gets like that if it’s unbalanced water, over crowded or not getting the right diet. If you can find live blood worms in your local pet shop, may help.

  2. We have a red tailed shark and had him since the tank was new. His with other fish tetras, mollys, guppies, plec, grammes female batta and Snail.In the past we added black molly and other fish with just vanished over night one by one. Could he of been him how as nipped the batta scale looks like it’s been stripped off mostly halfway down the fish to its tail, than started on the other side of bars. Even 3 spotted gramme under fin looks like it’s been bitten and is all red the same happened to an organ male molly and his side fin was ripped off completely. His around 1 year now.

    Thank you very much

    1. Sounds like the red tail has been bullying the other fish. Especially if its a smallish tank without much hiding space for him he may be getting territorial as he’s getting bigger.

  3. I have 3 red tail sharks in a 100 cm x 40 cm tank. 1 has outgrown the other 2. Had them now about 2/3 years. There are various other species in the tank, plenty of plants and various hiding places

  4. Hello.
    I absolute love my Red tail, he’s 18 years old had since I was 12. ? Just bought him a new 4ft tank to rule. Good article on him, Cheers.

  5. Hi there,

    I have 1 red tail in a tank with a platty and several cardinal tetras. Over the course of the last couple of months, the tetras numbers have dwindled (started at 10, now down to 6). I haven’t found a single carcas, so is it likely that the red tail is eating them whole? He has grown massively over the last couple of months so I’m wondering if this is the reason why.

    Also, I did a full water change around a month ago and ever since, the red tail spends every waking moment, upside down in one of the tank ornaments. I’m not even exagerating, I think I’ve seen it out side of the ornament 2 or 3 times in a month. I first thought he was feeding off algae inside, but now I’m not so sure. Before this he used to be quite shy, he’d swim around the tank but as soon as I went near it he’d hide in the plants. But now he never seems to swim, I only see his tail bobbing up and down from the ornament. Having read the info on this page, this behavior strikes me as being pretty odd for a red tail. Can anyone offer any advice on if I should be worried that I’m stressing him etc?

    1. He may have bloat if he’s been eating dead fish that’s very protein heavy give the tank a few days without feeding see if that sorts him out. Also avoid doing full water changes without using a large percent of the old water it’ll start a tank cycle again if you do that which has a high chance of killing all your fish.

    1. Not entirely sure could be stress they do lose colour if they’re stressed, could also be a disease bacterial or fungal.

  6. Hi,

    I have one red black tailed shark and ive got a 50 gallon tank. what other fish can i put in with it?
    ive looked at barbs? small tetras? angle fish? panda corys? and leopard danio? could i put in a eletric blue ram aswell?

    1. Avoid bright coloured fish and fish that use the same water space as the shark sharks seem to be mostly mid to bottom fish so get mid to upper fish. Pleco’s are fine as they’re armoured and won’t be bothered by the shark and big fish aren’t typically bothered by them

      1. I had also had two silver sharks with mine a rainbow and albino shark also with no problems.

  7. The pet shop owner told me to either buy 1 or 3 red tails cos of there behaviour so I bought 3 but still one of them chases another , 2 of them have doubled in size since purchasing but one has stayed the same size could it be cos it’s getting harassed bye another or is there another reason?
    Thanks 🙂

    1. Pet shop owners an idiot then. Unless you have a massive tank or get very lucky with the red tails its one per tank. I managed 2 in a 1000l tank

  8. I have a red tailed in with 4 glow Tetras and one pleco in a 20 gallon tank will that be a good environment for the red tail once he gets bigger? Just trying to figure out if I need to get a bigger tank or if the 20 gallon tank will be okay.

    1. You currently have a 90 Liter tank I would consider that a bare minimum for a growing redtail as it starts to get bigger it’ll want a lot more space perhaps double the size or more but make sure its a long tank as they like to swim not so much vertically but distance / speed.

  9. Hi im after geten a red tail but want to mo what size tank is tge smallest i can have him in id only b wanten a suker fish to clean tank and tge shark if red tail wil nd a big tank could you dugest a shark that live in smal tank like i said wil be on own except a cleanen fish thank

    1. I wouldn’t even consider putting a redtail in a tank smaller than 100 litres. They do get to quite a large size and like to swim about a lot. Mine dart along a 7 foot tank none stop. I think red tail is one of the smallest of the sharks I know silver sharks the other common one people buy can get to a pretty hefty size so wouldn’t consider one of them

  10. Hi, I have a 260 litre tank and I have 5 red tails, 2 silver fin sharks, 1 tiger botin (clown loach), 9 mollies (8 are babies, the other 15+ were eaten) and several other small fish that I can remember the name of!
    All my fish play well together or tend to leave one another alone.
    The 5 red tails share a boat that they all hid in, which I found quite a shock.
    I have recently put all the fish into a 50 ltr just whilst I do a full clean out and design change (with more hide holes) in the larger tank and have no problems with any of the fish.
    I have just been given a catfish though which is in a tank of its own at the minute as I am unsure of the temperament it will have with all my other fish. I am sure the sharks will be fine but will it harm my other fish? Its quite a large catfish.

    1. Almost all catfish are bottom feeders and won’t intentionally be aggressive to other species especially non-bottom feeders. There are a few exceptions of course and without knowing exactly what type of catfish I can’t say for sure but the chances are you’ll be fine. Having said that don’t put him in the 50 litre tank with the others 🙂

  11. Hi, I have a 80L Maidenheads Aquatics small cube tank and thinking of getting 1no red tailed shark. Currently have 4no Odessa Barb living in it. Shark suitable for this tank and with the Barbs?

    1. Wouldn’t recommend it the tank is pretty much too small for the size fish especially a red tail he’ll get very territorial and may potentially chase/panic/kill the barb’s

  12. hi, i only have a 53 litre tank with 5 neon tetra’s, im thinking of getting a red tail shark, what other fish can go with the red tail but they will not hurt each other?

  13. Hi i have a 500ltr tank with one 12 inch plec one 6 inch plec 3 catfish 3 discus two 6 inch oscars and a red tail shark lots of hide holes and cover but other than the big plec chasing the small one and the occasional tough guy act of the oscars my red tail shark looks really happy and the tank is placid

    1. Plenty of space and hidey holes he’s probably perfectly happy and settled in + with most other fish being bigger than him or armoured he’ll just keep himself to himself.

  14. I have a red tail shark in a 10 gallon tank with platys. It is just fine and isnt agressive at all.

    1. Hi I’ve just had to remove my red tail out of a 3ft tank and swap it over with a male betta. Betta is fine with the other fish had to swap them over because red tail did not stop chasing the neons. But now I’m worried about him being on his own ?. He seemed fine with the platy I had so should I put the platy in with him. You said yours get on fine together.

      1. Mine do as do many others looking at the comments but every fish is different what happens for me may not happen for everyone else. He’s probably just a grumpy fish and wants to be on his own there’s no real requirement for other fish with him so its entirely up to you whether you want to put the platty with him or not

  15. I have a red tail shark but all his fins are red, not just his tail.bas it grows will it’s fins turn black

    1. They’re more often called ruby red tailed sharks. They’re not massively common these days in the primary black colouration but they are common in albino’s which have all red fins. You’ll probably find the front fins go darker red / almost black over time

      1. Yes they are getting a little darker especially the bottom fin (not sure the actual name for it) it’s getting a bit of black on it. I recently moved my shark, everyone will think I’m crazy but it’s working shockingly well so far. I have a 100 gallon tank with an Oscar in it close to a year old and I wanted another fish in it so I took the shark and clown loach from my mothers tank and put them in the 100 with lots of pipe to hide in and other hiding spots and my Oscar just ignores them and they do their own thing.

        1. Tyler, the shark that you described is more commonly called a rainbow shark. All black with all fins being red. Do a image search of a ‘ruby red tailed shark’ and a ‘rainbow shark’, you should see no difference. But from my dealings with fish aquariums in my area, they know your shark as a rainbow shark.

  16. I have a tank of 200 litres, with a red tail shark, 6 tetras, 1 plec, 3 mollies and 2 guppies. A couple of weeks ago one of the mollies disappeared from the tank, I looked everywhere, took out all the ornaments and plants, even searched for it in the gravel with the vacuum, but no sign of it. Today I noticed that another mollie gone missing. I have a feeling its the shark that’s been eating them. I had the same when I first got the tank, when a couple of tetras gone missing, and the shark would chase them all the time, so I guessed he became more aggressive than usual and actually ate them as they are quite small. But the first mollie that disappeared was quite big for it to be eaten in a night. Any ideas? The shark is my favourite in the tank and I want to find fish that he’ll be happy with, and not eat them :/

    1. Mollies are jumpers they will find a way out of your tank no matter how small the gap. If the retail has been doing its usual trick of chasing things around it could have forced it to jump.
      Check behind your tank for dried up dead fish. Sharks chasing other fish is more common in heavily stocked tanks or small tanks they’re very territorial.
      The red tail will be fine with any bigger fish but smaller fish are typically an issue. My retail is very passive but he’s also the smallest fish in the tank

  17. i have 2 red tailed sharks in my 20 gall tank along side tiger barbs blue terra’s orange guppies, and 2 silver sharks the only one the red tails chase is each other

    1. That’s because the tank is massively too small for 2 red tails there isnt enough space for them both to have their own territory so they’re fighting. Get rid of at least one of the red tails or buy a much bigger tank.
      Also get rid of both silver sharks. A 90litre tank isn’t even big enough for a single shark let alone 2.

  18. I’ve had 2 sharks and the both jumped out of my tank even though my lid is on tight one died but with the one I have now I managed to get it back in the tank and it’s fine now but I get really scared incase it happens again

    1. Are there small holes in the back of the lid where the filter/electrics run in its quite amazing the small gaps they can jump out of. You can usually stop them by putting some plastic meshing over any holes etc.

  19. I want to get a red tail shark I’ve been doing a lot of research but I’m finding it hard to get consistent info on them I’ve seen that I should get a 55 gallon tank but then I’ve seen that it’s fine to have a 20 gallon and I have a few more questions if someone can help me out but if you don’t really know what your talking about please just don’t say anything because I don’t want to be miss lead

    1. 20 gallons is much too small for a red tail. a 55 gallon with a fairly high water flow rate would be perfect for one perhaps even 2 if its a long tank give them room to avoid each other. They can get to be fairly big fish and they can bully especially smaller fish. Having said that I have one in a 1000L tank and he’s never any bother he has a piece of ceramic pipe he lives in and he rarely comes out apart from for feeding and I’ve never had any bullying issues with him he’s now 3-4 years old and fully grown has maintained a lovely deep black colour and his fins have remained really bright red.
      It has to be said they’re not very interesting fish for the viewer since they don’t really do much (at least mine doesn’t) however they are very good looking fish.

  20. I have my red tail with 3 bala shark,3 guppie,3 mollies,3 kuhli loach a pleco and a zebra angel fish everybody gets along but every now and then the red tail chases the biggest bala shark which is about the same size as the red tail (about 5 inch)
    Also, the red tail seem protective of the guppies and mollies

    1. Thought I’d post an update….
      2 years later everybody remains but one bala shark vanished( I believe he jumped out by the filter opening and the cat got to him)
      The red tail still chases other fish away from the guppies and mollies.
      We added another zebra angel fish and a ruby shark everybody still gets along and the angel is now pregnant
      so now my question is, is all gonna be ok in a 75gallons tank ? Or should I upgrade the tank to accommodate the baby angel when ready to go back to the big tank

      1. If you want to keep the baby angels then you’ll need a tank remember angels are egg layers though they stick their eggs to glass surfaces or cones they dont carry their eggs. If your angel is looking fat it’s probably bloat not pregnant

        1. How can I tell the difference?
          Also everybody else is normal and behaved no change in diet she’s been gaining weight for the past 3weeks and if she is pregnant,when should I transfer them into the nursing tank?

          1. For angel breeding you’ll need an empty tank with airline filters not pumped filters angel babies are tiny you want a cone or a rock in the middle of the tank female lays eggs on cone then both female and male will guard the eggs picking them up and putting them back on cone if they fall off. Couple of weeks later they hatch when they do move parents back to main tank.
            You can tell when a pair is ready to breed as the big male will guard the female somewhere in your main tank and chase the rest of the rush away.

  21. I have one red tailed shark ans 12 neon tetras. My Red tailed shark has never done anything to the neons. Is this just because I got a nice red tailed shark?

  22. I never see my 6″ red tail eat. I guessed he eats at night when the lights are off? I expected to see him scavenge or go after the blood worms and brine but he just gets
    territorial when food shows up. He is healthy for I guess I shouldn’t worry.

  23. i adopted one to. but i dont know what to put it with like other fish??? i want this tank to be bright and coloured fish so plz reply to me soon.

    1. Bright and colourful fish that’ll play well with a red tail (at least they do in my tank)

      Small fish – Harlequins
      Medium/Larger fish – any plec, rainbows, denison barbs, most angels I’ve never had an issue with, silver sharks are fine too.

      Avoid things like rams/siamese fighters etc with fancy fins and avoid other red tails.

  24. ive read i can put my red tailed shark in with malawi cichlids is this correct there is only 6 of them in tank and tank is 70ltr lots to hide under…

    1. 70l is far too small a tank for a redtailed shark you need at least 120 ideally 180 for one as they can be very violent in small tanks not to mention they get quite big themselves mine is about 7inch long now.

      Its also a little on the small side for cichlids too if I’m honest

  25. Ive had a redtail shark now for six month with a catfish and guppies my catfish is about one foot long and my shark is six inches long they both share the same rock just lately the catfish as started to push the shark out so ive put another rock in the tank i have is 4ft would it be best to take the shark out as the cat ive had for two years also in ya write up u never said the life span of the shark

    1. My large common plec sometimes chases the redtail around. If the tank is big enough they should settle down after a while. Rather than rocks try putting in some tubes either plastic drain pipe or I use ceramic pot drain pipes. Put in a couple and you should find the plec goes in one and the redtail in the other. If they’re bickering its probably more of a territory / hiding space issue rather than outright aggression.

      I don’t think at this stage there’s any reason you should split them into different tanks.

      I never put their life span as I have no idea I’ve had mine for about 5 years now its fully grown but not died. I don’t know of anyone that has had one die of natural causes / old age so I have no idea of the final age range of them.

      1. I’ve had my redtail about 4years now and it’s about 5-6 inches. I read that they live 8-10 years

        1. I have no idea how long they live mine is about 5 years now I guess can’t remember. Sounds like yours is roughly fully grown though

  26. Hi I’ve recently adopted one of these fish to I have read up a fair bit but the answer to my question I can not find can this beautiful fish eat your other fish over nite with out a trace I have 2 fish that have completely disappeared thank u in advance for any helpful answers

    1. Its very rare they’ll actively hunt and kill other fish however they can be bully’s which can stress and kill other fish. While redtails are mostly vegetarian like most other fish they will peck at and eat a corpse in the tank they won’t eat everything though so there’ll usually be something left to need removing from the tank.

      If you can’t find any corpse etc in your tank check behind it! some fish are jumpers and may have decided to go carpet surfing and be dead behind your tank stand. If you have cats they’ll happily eat any body lying behind the tank for you leaving no trace. Failing that take all the decoration out of the tank and with abit of plastic just waft all the plants and substrate you may find a corpse comes floating up and you may just have not noticed it blending into the substrate.

    2. I have found that angel fish as they grow will happily eat the small fish like neon’s and guppies, also most fish will eat a fish small enough to get in the mouth, never known a red fin to eat a fish to be honest they just chase them

  27. Hi this really helpful thanks ive adopted one but with a black tail is this possible or am i being an idiot and its another species of cat. cheers

    1. You certainly can get all black sharks, you can also get albino sharks with all red fins and ruby red sharks which are black with all their fins red

      1. I had an american clawd frog and it ate my 4 inch bala shark in a matter of 5 days. never knew a tank frog could eat that!!!!

        1. I guess i was just lucky with my red tail! I had him for about 7/8 months i would say his named redbull and althought his still a baby his MASSIVE. Litterally i mean massive he is nearly the same size as my pleco and only a baby still, i feed him blood worms, algea, protien pellets ?? the shark gets along very well with everyone in the tank however i had tiger barbs and they were really good together and when i decided to keep some gouramis the tigers will go crazy so i rehomed them as i wanted to house more comunity fish but not my gouramis keep dying which i bought a week ago i had 5 now only 1 within in 1 week and all the other fishes are fine i guess they cant handle the water flow as i have 2 water flows and the shark sometimes swims up to them to say hello for a couple of seconds but he doesnt really chase them just swims by them so dont know why the gouramis a dying….. Well im planning to keep only a shark in my tank anyway as its out growing and i want to keep him healthy so far i have 1 red tail, 1pleco, 2shrimo, 2loach and 2 gouramis in a 25 gallon 50cm each side a rectangle tank :)))
          Just noticed today aswell that my shark must of scrapped his scale on something as he has a bold patch near his gills but his perfectly fine swimming fine the nornal redbull feeding well so i guess he just hit himself agaisnt something, clumbsy shark ?

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