Rainbow Shark

Scavenging for food in the gravel, Soumyakundu's Rainbow Shark is a beautiful example of the Epalzeorhynchos frenatum species. A member of the Cyprinidae family, this fish is commonly stocked in the freshwater community fish tank.


The rainbow sharks blackish-green body is accented by colorful reddish-orange fins. Also known as the Red-finned Shark, or Ruby Shark, this fish is primarily a bottom, and mid-level dweller. They're happy eating most anything. Spinach, lettuce, tubifex worms, algae, and leftover fish food, make them happy.

The Rainbow Shark is a semi-aggressive fish, which can also be very territorial. It's suggested you have just one in the tank, and fish in similar size. Also, it's best to avoid combining the Rainbow Shark with other freshwater sharks, such as the Red-Tailed Shark and Black Shark. Here are a few more characteristics to consider:

  • Grows to 6 inches
  • Tank parameters: 73-80 F; pH 6.5-7.5; KH 10-15
  • Minimum tank size is 30 gallons; 50 gallons preferred
  • Requires moderate care
  • The rainbow shark is an Omnivore

Rainbow sharks are compatible with most barbs, danios, loaches, plecostomus, and the gourami. You just have to make sure and leave them space to establish a territory.

Breeding the rainbow shark in an aquarium setting isn't done due to the sharks aggressive behavior. If you've got the room in your fish tank, and proper companions, the rainbow shark can be a fun fish to keep.

109 thoughts on “Rainbow Shark”

  1. Can they mate or not. No sites say if they do and at what stage do they mate. How dose the shark look when prgnant.
    I have a 100 gallon tank and I have three rainbow sharks.
    Two of them look like they were doing a mating dance and now one of the sharks have a big belly. Can she be pregnant.

  2. i have 3 rainbow sharks and 3 assorted long finned fish and when i try to feed them the long finned fish eat all the food before the sharks get some. I dont know what to do. Do you have any advice

  3. I have one of these got it today and i just have to say wen u get it and it sees you for the first time its always very calm my brother also has a silver shark that is jumpy very jumpy but these two sharks get along very well

  4. I still do not see how to feed this fish, when other fish are eating all the food before it gets to the bottom.

    Can someone help?

  5. This is an interesting and informative web page. I have recently bought a 65L fish tank and currently have 2 X-ray tetras and 3 Black Widow ones – they’re not getting on badly. In a few weeks I am hoping to add something more interesting, like a Red – Fined shark or possibly a Red – Tailed Black Shark: 2 things, firstly, which would you recommend for a beginner ?, and secondly, would either of them not get on well with my current fish?

  6. Hi Ed,

    I had a red tail black shark, and can tell you, they are very territorial. I had him in a tank twice the size of yours. I definitely would not recommend it for your tank.

    If you’re looking for something that’s active, you could probably get away with 3 tiger barbs. There are also many other types of tetras. You could continue there too.


  7. Well, I just purchased three baby rainbow sharks, about, maybe two inches a piece at most. They are happily settled in a cozy heated ten gallon tank, the only inhabitants. How lone til I need a bigger tank? And umm, why didn’t the petstore tell me that they require different accomadations? Thats really annoying. But i like my little sharkies.

  8. I have a 30 gallon tank, 2 logs on bottom with places to hide under, fake coral, cave, 2 live bamboo shoots. Rainbow shark, 2 average sized angel fish. Had one molly but randomly was pecked to death. I just intoduced 5 pristella tetras to the tank and the rainbow shark chases them all day long nipping at their fins. the tetras try to hide but after 2 days had to put them in baby net because their fins are almost gone. what should i do? or why is my rainbow shark so dang aggressive? water temp 78, ph 6.8-7.2 fed tropical fish flakes and brine shrimp. any suggestions?

  9. I had two red-finned black sharks, they are were in a nice medium tank with three guppies, two bottom feeders, and three other fish. After a few weeks in the tank, one shark, and two guppies were gone. I’ve seen the remaining shark nibble the only remaining guppies ail fin. The shark is also much fatter than when we first got him. Is the shark eating my other fish? If so, should I move the shark to another tank? He also chases the other fish, but they’re too fast for him… My guppy however is not so fast.

  10. I think my rainbow shark is gonna have babies. How would you know? Mine has the bulging stomach and it stays in the same place in the corner of the tank in a facing up towards the top of the tank and has been in that same area for about a week and won’t even move to eat. I have to make sure the food drops directly on top of his mouth. Does anyone know what this means?

  11. That sounds a little scary, do you ever see it’s fins move? or it’s gills? You need to make sure your fish is still alive…But if you do see it is in fact alive, then I would say it is most probably pregnant, that is, if it is even a female.

  12. I’ve been doing some research on your pregnant question, the main question about this will need to be answered immediately for the sake of your fish. My question is simply this; how long has your fish been in this condition? and which part of the tank is the fish in, is it near a plant or fake rock or such? Your fish may be laying eggs depending on the amount of time it has been in this condition. Please get back to me as soon as possible, thank you.

  13. Cyprinids do become gravid, but not pregnant. These fishes are egg scatterers and there needs to be a male present to fertilize thge eggs as they’re released. Unlike guppies, these fishes do not have internal fertilization and the eggs do not develope internally after fertilization.

    Fishman Jack

  14. Hi Mike,
    I read your interview over on site meter and decided to have a look see for myself. I love your site, it brings back memories of my father. He had a 50 gal. tank in our living room growing up, he had tinfoil barbs, and neon tetras with a rainbow shark, I believe he had some angles in there at one time too. I loved watching the little shark. He lost the neons when the power went out in an earthquake and they were the only things to be seen by the others. In the aquarium.
    Wonderful site you have here!

  15. i have a 55 gallon tank with 2 albino rainbow sharks 2 zebra dainos 1 ghost shrimp 1 kuli loach 4 red phantom tetras 3 swordtails 3 mail fancy guppies and 5 female and 6 tiger barbs and everyone gets along just fine but i also having a issue with my one shark not really swimming that much and hidding in a cave most of the day alone and its belly is about twice the size if not a lil bigger compared to the other shark but i too could not fine any info on there breeding habbits

  16. Rob,

    I couldn’t find any more info on possible pregnant rainbow sharks. I can only suggest keeping an eye on her. Especially if she stops eating. I’ve heard epsom salt added to freshwater aquariums can be beneficial. I’ve not tried adding it, but you may consider that if you decide it is constipation.

    If you’re feeding more than once a day, try cutting that back too.

  17. also is it at all possible for a guppy to get a sword tail pregnant because i got a guppy that is the same colors as my pineapple sword tail and he is totally confused he(guppy) never leaves the sword tail’s side constantly trying to mate with her…and now she is in fact pregnant and my only guess is that he some how succeeded i have a male red and black velvet sword tail but he doesn’t go near any other fish hes a loner lol

    thanks for the help with my shark he/she is doing fine i think its just a fattie

  18. I have one rainbow shark, two tiger barbs, 1 gold gourami, and one platy. I woke up this morning and noticed that my rainbow shark which is growing very fast and is about 5 inches was litterally eating the gills of the platy and trying to eat it. I immediately removed the platy to see if it would recover. It is still alive but very stressed. Should I feed my rainbow shark a feeder fish, and will it eat feeder fish. I bought one tonight, about one that’s only half inch long and really quick and it seems that the bigger fish can’t catch it. What should I do?

  19. My mom’s room mate has had a rainbow shark for a godd many years. Just over the course of the last couple of days, he has started laying sideways. He is also hanging out around the top of the tank. Sometimes he rolls all the way over (like a dog). He is still breathing and he swims around while he’s sideways. Any clue as to whats wrong with him?

  20. ok i have a rainbow shark in my tank along with some other fish. and when i feed them the other fish eat all the food and the shark doesn’t even try to eat? so do i need to change fish food?

  21. Upon the recommendation of my local pet store I recently added two rainbow sharks and three tiger barbs to a 10 gallon tank. Those are the only occupants. I am becoming concerned that they will dramatically outgrow their accommodations. Am I justified in this concern?

  22. I just got a albino rainbow shark a red tail and a normal rainbow.. they are still young but seem to get along with minimal aggression.. is it possible for this to work?? im thinking eventually ill have to buy another tank…???

  23. I have a 25 gallon tank. I ws told by a person in the pet store that my shark will out grow the thank within a year. It has already eaten most of my other fishes. The only fish it won’t is my two cat fish.

  24. I just got two rainbow sharks yesterday, and so far we have had no problems. It is a 10gal tank and we have two angelfish in with them. The sharks have stayed on opposite sides of the tank hiding under our plants. Should I buy them a cave or something to hide in other than just the plants

  25. My tank started with a bala shark and a rainbow shark.. The bala died 2 months in. I bought another rainbow shark and he only survived 3 weeks because he was smaller than my original rainbow “sharkie”. That was about 1 month ago.. Today I woke to feed my fish and there was another little guy in there. She clearly had to of had this baby.. The baby is pretty big so i don’t know what I should do. Sharkie has been hidind behind the filter all morning. Are more babies on the way and should i take the new little one out?

  26. Hi,I just bought a 2nd rainbow shark and It`s not working out.as soon as he hit the water he`s chasing everything in site,taking him back

  27. If you recently bought them, they may have already been sick. I’ve found that tiger barbs will look for trouble if they’re not kept in larger numbers.. 5 or more. Even then you don’t know, but I keep eight barbs with tetras, so my guess is that you’re sharks weren’t healthy to begin with.


  28. oh thanks i just baought a rainbow shark 3 zebra cichlids and 1 lepord cichlid all are small fish and doing well they all get along fine i azlso bought another tiger barb hes small and green and he loves the two older ones 😀

  29. Our rainbow shark has suddenly stopped swimming – it’s almost as though the shark is too “heavy” – he tries to swim up, but just keeps sinking back down to the bottom – the head is pointed up (so he looks like he is on the diagonal – head is higher than the back fin).

    When he gives up on the struggle to swim, he sinks down to the bottom of the tank and just lays on the gravel. I believe we have had him for around 8 months, and the problem has just started yesterday. He seems sluggish and it appears that it’s difficult for him to move.

    His body doesn’t have any unusual markings, but when you get close to the tank, he moves into a corner that he can hide in.

    Anyone have any ideas for what could be wrong with this guy? He had been extremely energetic. We changed the water on Sunday

  30. Hi, I recently got what I think is a rainbow fish, it looks exactly like the picture above just white instead of darker, but still with the orange fins. Anyway, my question is, I had previously had a beta fish and still have a ton of the food left over (it recently passed away) and I have been feeding the rainbow fish the beta food because the employee at the store we bought it said that was alright but I have noticed now that he will not eat the food. Does that mean he may be sick ? or that I should just try to find something else for him to eat. Also, I do not have him in a large aquarium, just a large fish bowl. Im obviously new to this fish keeping thing, any help would be great!

  31. I have three rainbow sharks, one is 8 years and the other 2 are 2 years. The 8 year old shark in the last week has almost doubled in size. Could she be pregnant.And do they have eggs or is it a live birth. My tank is a 50 gallon and have 9 other fish..

  32. My Rainbow Shark had beautiful red fins a week ago, but now his fins have faded to a light pinkiish orange color and his belly is turning kinda white. What do you think could be wrong with him? I feed him twice a day. There are two other smaller catfish like bottom feeds in the 15 Gallon tank with him.

    Any suggestions?


  33. Try feeding just once a day. I used to feed twice a day, but now only feed once/daily, and my fish are doing fine.

    As for the color change, I’m not sure. It’s possibly sick. I’d try searching for those symptoms.

  34. I got one of these today and when i put it in the tank i went to go get the lid and when i came back it was laying on the counter. I tried to put it back in but it was dead. This fish was the last fish i thought would be able to jump out since it usually stays at the bottom of the tank.

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