Redtail Catfish: Diet, Tank Requirements, Temperament and Tank Mates

The redtail catfish is a very fast growing, extremely large freshwater fish.

It is one of the most attractive members of the catfish family.

In the wild it inhabits large rivers, streams and lakes and is native to the Amazon and large waters throughout South America.

It is highly unsuitable for the majority of home aquariums due to its size, yet it continues to be sold in fish and pet stores.

In this article we will give you all the information you need, to make an informed decision about whether or not you have the capacity to house and successfully look after a Redtail Catfish.

Category Rating
 Care Level: Difficult
 Temperament: Aggressive
 Color Form: Dark Gray/Brown,
 Lifespan: 15+ Years
 Size: 4 – 6 feet
 Diet: Carnivore
 Family: Pimelodidae
 Minimum Tank Size: 1000 Gallons
 Tank Set-Up: Sparse/Bare Tank

About the Redtail Catfish

About the Redtail CatfishThe Redtail Catfish belongs to the genus Phractocephalus and is the only known species left.

It is also known as the flat-nosed catfish, RTCs, the antenna catfish and the banana catfish.

It originated from the South American and Amazonian rivers, and can be found in Brazil, Peru, Venezuela, Colombia and other neighboring countries.

They have a long lifespan and can live in excess of 15 years if cared for correctly.

While they begin quite small in size (around 5cm) they quickly grow too big for most aquarists’ tanks, and will often be donated to public aquariums. However with the frequency that this is happening at, it’s difficult to find a zoo or aquarium that will accept privately kept large fish.

So, before we go on, if you are uncertain that you can care for a fish of this size for the duration of its life, we recommend you avoid this fish.

RTCs are mostly kept by professional, experienced aquarists.

Redtail Catfish Appearance

Redtail Catfish AppearanceRedtail Catfish are large and colorful. They have long whiskers (i.e. barbels) on their mouths, and a beautiful red tail.

They are mostly dark grey/brown along the top side of their body with small dark scattered spots, and a paler yellow/white wavy white band which stretches down both sides of its body.

It has a cylindrical shaped body, with a flat belly and a laterally compressed tail.

The top of the dorsal and caudal fin are a red-orange color, and it has three pairs of long barbels; two on the lower jaw, and one of the upper jaw.

Typical Size and Growth

When juveniles are imported into pet stores, they are usually around 5cm long.

You might have been told by your pet-store that this fish will only grow up 12 inches in your aquarium. This is not true. The myth that a fish will only grow to the size of its tank is a really dangerous one amongst the aquarist hobby.

These fish can easily grow an inch a week when they’re young; most of them reach two feet within a year.

They can reach lengths of over 4 foot in home aquariums and left in nature, they grow even larger.

The largest recorded Redtail Catfish was found in the Amazon River in 2010, and was 63 inches in length and weighed 123lbs.

Redtail Catfish Diet

Redtail Catfish DietRedtail Catfish are not picky eaters. In fact, they’ll eat anything that fits into their mouth.

They are omnivorous, but prefer meaty foods. Ideally, the RTC’s diet should consist of sinking carnivore pellets, cut fish and meat, shrimp, crayfish and worms. You might also want to make your own food to ensure they’re getting the best diet possible.

Although you’ve probably seen videos of live feeding on Youtube, it is not necessary. Feeders are often grown in unsuitable and crowded conditions which results in many problems, one of which is that they have little, to none nutritional value.

They could also be carrying disease and parasites which may infect them. Additionally, live feeders are expensive compared to healthier and more nutritional alternatives.

Overfeeding is a common issue amongst this species.

These fish become very sluggish after each feed and require time to digest their food properly. Juveniles should be fed every other day, but as they mature they will only require one large meal per week.

Once you get to know your fish, you can watch for signs when they are sluggish. You’ll notice when they become active again and will get to know when to feed them.

They can be trained to accept food from their owner’s hands.

When we say they will eat anything that fits in their mouth – we mean that literally. They will eat gravel, stones, filter parts, basically any loose parts. We’ll cover this in the tank requirements section.

Behavior and Tank Mates

Behavior and Tank MatesA juvenile catfish can be very shy. Some suggestions to help them overcome their shyness include: providing cave areas for them to hide out in (make sure they’re not small enough to eat) and keeping the tank in an area where you spend plenty of time so they get use to interacting with you.

Ideally you should house Redtail Catfish on their own.

If you really want a tank mate, make sure that whatever you put in with it can’t fit into their mouth.

They can easily eat anything that is half the size of them, and will even have a go at eating things that are larger than half their size – this can be fatal as they may choke.

RTC’s are natural predators and will attack and eat smaller fish, so any fish that are smaller than them are not suitable tank mates.

Tank mates should be a similar size; appropriate fish include: Gars, Stingrays and Datnoids. It’s also best to house them all together from a young age.

You can house RTC’s together, the chances of them breeding in a home aquarium are very low, however you should also know that there aren’t any distinguishing features to determine their sex at the juvenile stage.

Tank Requirements

Tank RequirementsRTC’s require huge tanks, such as the ones you’ll find in aquariums and zoos.

If there is just one piece of advice to give about the tank – only buy the fish when you have a huge tank. Don’t buy one; thinking you’ll buy a larger tank in a year or two, because people very rarely will.

There is a lot of debate around the size of an acceptable tank for this species.

We recommend as a bare minimum, this fish will need a 1000 gallon tank, which should be at least 12 x 4 x 3 foot, even this size would not be appropriate for a fully grown RTC. Many people decide instead on indoor ponds for this species which is a more appropriate housing solution.

We mentioned before than this species will literally eat anything that will fit in its mouth, so therefore they require very sparse tanks. Avoid decorations, gravel and loose parts in your tank.

In terms of substrate, they’ll eat stones and gravel so ideally you should have a bare bottom tank, but if you really don’t like the look of bare bottomed tanks you could use a layer of sand. Keep in mind that a bare bottomed tank is easier to clean.

They are middle to bottom dwelling fish and prefer low lighting.

Redtail Catfish typically live in a tropical environment, so their tank conditions need to match this. Their water should be kept in-between 20 and 26oC (68-79oF).

You’ll need a water heater if you’re in a climate that regularly drops below those temperatures. You should keep the temperature as stable as possible.

The pH should be between 6.0 and 7.5.

Given the size of the tank, you’ll find it near impossible to find a traditional filter that will be effective so a sump filter is the best option.

Commercial sumps tend to be very expensive, so you may want to construct your own if your budget doesn’t allow for a commercial sump.

Should you keep a Redtail Catfish (Summary)?

There really is only one question to ask yourself to help decide whether you want to keep an RTC. That is, can you provide them with the best possible life for the duration of their life?

This encompasses a large enough tank, preferably a pond, the time commitment to feed and change the water and being prepared to research and care for the fish.

If you are committed to providing a RTC with all of this, and you like the thought of caring for such a huge fish, then a redtail catfish is a beautiful and very unique fish to keep.

Let us know below if you’re thinking of getting a Redtail Catfish, or if you have any experience in keeping them. We love hearing your stories…

Robert Woods Portrait
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.

32 Comments

  1. I plan on getting one this Monday I have a tiger shovel nose catfish already I’m building a pond for them both my pond is gonna be 8×8 5 feet deep. I’m very excited and can’t wait to own the little guy

  2. thanks a lot.
    this stuff is easy to read and understand.
    although it made me not to buy a red tail catfish because I do not have a big enough tank… 🙁

  3. I saw a beautiful 10″ retail in a Petland in the West Village NYC. It is in a tiny tank way too small -maybe 20 inches. It was heartbreaking to see. The woman at the counter told me a customer abandoned it in the store in a bucket and they were required to keep it.
    I am not a fish person per se but I would would love to help this beautiful fish be in a better situation. Any ideas?

    • Hi Barbara,

      Unfortunately this happens all to often. Are you able to provide it with the tank size and all the conditions we have covered above?

      Robert.

  4. We have a huge Koi pond out back and I recently purchased 3 of the redtail cats to put in the KOi pong. They are all very small at this point, but 2 of the 3 have disappeared. None of the KOI are missing, so I don’t think it was a predator, but I can’t find a dead fish around the sides either. Any clue what might have happened to them?

    • Hi Scott,
      What a mystery! No suggestions unfortunately, do let us know if you ever find out. Be careful are the other RTC grows – it may eat your koi!
      Robert

  5. I recently brought a pair of Redtail Catfish about 2inches in size. One of my catfish died 2 days later. I fed them tuna the night before one died. The other one is doing good and looks healthy. But he is alone in the tank now. I have setup everything in the tank for them heater filter and hiding place. Heater is set at 26 degree celcius. But I don’t know what happened. I just found him at the bottom of my tank dead. Can you help me with what happened to my catfish and should I buy another catfish for my other one or will he do good all alone. Now he is in a 100 litre tank. I’ve ordered for a 1500 litre tank. Will get it next week.

    • Hi Melvin,
      It’s difficult to know the exact cause of death of your RTC. A 1500 litre tank is still nowhere near big enough for even one RTC. We recommend a minimum of 1000 gallons, which is around 4500 litre tank.
      Robert

  6. I plan on getting 2 RTC and i was wondering if a 20 x 6 1/2 x 3 1/2 foot pond was big enough for them. Also wondering how big of a red tail a 50 gallon tank could hold as a growing tank as i plan to get babies and don’t have room for a bigger tank.

    • These guys grow extremely fast, there is no way a 50 gallon tank will last them more than a couple of months.
      It’s important you get them into their final pond or tank ASAP so you don’t stunt their growth.
      Robert

      • Understood, but I am just using the 50 gal tank to grow them out large enough to be put into the pond which will be 20x8x5 feet. Will that be large enough to hold one for its’ entire lifespan?

  7. Would koi fish be a good pond company for a redtail cat I’m wanting to get both but I want to make sure an what size the pond should be any tips would be a huge thanks

    • It really depends on their size. As a long term solution, I would say no. I have known RTC’s to eat Koi. Thanks, Robert

  8. Hello folks. I’m thinking about putting a lake on my property in southern Spain. I have some experience with red tails as I’ve caught them in asia. My question is with regard to water temperature and if they will be able to survive in Europe in an outdoor lake. It’s not so cold like most of Europe but winter temperatures can fall to 16-18C in the daytime and 10-12C overnight.

    I see these fish a primal survivor types having handled many of them. In fact I’ve often joked you could fire a bullet into them and they would survive they are that tough.

    The only question mark I have really is the water temperature thing? Can anyone help me out?

    If RICS are a no go I am thinking about some goonch of Indian origin. I want to grow a few monsters so I’d also be happy to heat if anyone has any other ideas of what I could happily stock into the lake in such a climate? Wels cats I am not a fan of by the way which is the indigenous variety here in Europe.

    Grateful for any and all info

    • This sounds like a great idea, I’ll leave your question here in hope that someone has a similar experience to share tips with you. Thanks, Robert

  9. Can you have them in an outdoor pond without a heater and store them in an indoor tank during the winter? In southern Cali btw.

    • As long as the temperatures that they stay in remain in between 68-79oF and stay as consistent as possible. Thanks, Robert

    • Hi Tyler, the color should develop within the first few weeks. If it’s not red it could be a possible indication of stress. What size tank are you keeping your RTC in? Thanks, Robert

  10. I hve recently bought two baby Rtc’s and looking forward to give them healthy habitat in pond which I have in backyard once they grow. Presently kept them with silver Arowana. Nice article, helped me to understand RTC in much better way.

  11. I need help…I ordered a Zebra Plecostomus from an online store for $4.99. Stays smaller and easy to care for. I get this nice package in the mail, perfectly packaged and transported very carefully and open it up and wouldn’t you know….they sent me a Red Tail Catfish by mistake and they refuse to take it back as I made the mistake of putting it in my tank (I wasnt going to leave him in a bag inside a box and take him to the post office for Christ’s sake). I have a 30 gallon tank and cannot find anywhere suitable for this little guy to go…I’ve even started calling aquariums but they’re also picky because he is in a private residence tank. How long can a tiny 30 gallon tank sustain him while I search for his home? I have a 320 gallon tank that I haven’t had set up for almost 5 years, but even that I don’t imagine would last more than a year, two tops. Any advice is greatly appreciated.

    • Hi Kris, I’m sorry to hear about this. If possible I would get him into the 320 gallon ASAP, he’ll grow out of a 30 gallon within weeks. I really hope you manage to find a home for him. Are there any specialist fish shops near you? I’ve found that private ones are more likely to take on these fish than chain stores. Let me know how you get on. Thanks, Robert

  12. Can someone tell me if my fish got some disease. We got two baby RTCs and today we noticed clear bubbles on their whiskers. What could this be? Both of them have it. Please help!

    • Hi Alex, do they have any other symptoms? Is it possible they are just air bubbles? Thanks, Robert

  13. Although I very much agree with the comment of having a large enough system to house an adult instead of buying these cute guys small and as they grow get a bigger setup as this unfortunately rarely happens. And these guys grow fast, faster then your imagining if you’ve never had one. But I’m here as a rarity because I committed. As my first “monster” fish, 1st monster tanks, 1st DIY tank sump filter builds, I had to pick these guys as they are stunning and very personable like water puppies. Knowing I was going to build a huge setup, a dealer friend of mine got an order in and had to show me and I fell into it. I had to have one now..lol.. and ground had not broke on the pond build. So began the ever so quick tank upgrades: 20gal(pointless), 40gal, 55gal short, 75gal, 110gal and now to a temporary 660gal pond. Now to give an idea of the speed in which the upgrades took place, at 2.5 inches in a 20gal to now a 8.5 foot × 5.3 foot × 2 foot deep 660gal above ground pond has taken place in 6 months with a 20+ inch Redtail and a 14inch RTC×TSN hybrid. With all the collected free or cheap materials i could find and most items bought at msrp were not originally marketed for fish keeping but do the job as well or better and assembled filtration and temperature control systems and it still cost me a few hundred(trying to keep costs down to put into the final habitat) just to put this 660gal together and it’s only temporary until the 2000gal is finished. And trust me a few hundred on a temp 660gal is nothing compared to a 2000gal setup even designing and building it myself it will be more than $1000usd just for materials. Now I say this as a warning but in a good way, just be ready. I committed and have done what it takes to keep up that commitment but it is and will continue to be a whole heck of a lot of work and for now it’s all being done for just 2 cat’s. And even if it where 1 cat the same amount of time, energy and money would have gone into the care. And yes money: upkeep(filter),energy(multiple pumps(water/air),water movers, heating/cooling with thermostat controller, water, oh and food. I dont think enough people remember to think about the food bill with any type of pet, but especially “monster” fish like these. If you have ever had a medium to large dog on a straight one brand dry diet food think of that and imagine 1 redtail costs more to feed in its first year (as I can only speak to the first year) then my full grown Siberian Husky during the same time span. So as a take away, yes wait until you have the proper size setup before even buying a little RTC it will save you a ton of work though I would still say it was/is worth it but unnecessary, plus some like mine do not like a constant and significant change to their environment causing stress in my case food strikes. I’m self admitting this as my number one reason not to go the route of increasing your tank size as they grow even if you can keep up as a rare case with the required space requirements, as it can cause unnecessary stress to the fish and you . 2 please dont look at the price of buying a fish as your biggest expense with these guys its many times over their costs to care for and feed them every month. Water alone, find your water bill and note your cost, 100gals every 2 weeks to top off from evaporation and 50% about 300 gallons every 2 weeks for a water change. That’s 800 gallons a month and this is after 6 months. Their final enclosure I’m estimating approximately 2200 gallons a month. On that note take up gardening as this amount of natural liquid fertilizer and water should not be wasted. And one more note keeping a large pond inside if you have the space is an excellent way to save on heating and cooling however if it shares the air of your living space it will make it quite humid and typically the temps at which they are kept are warmer than most peoples typical inside settings and that large body of water will warm the surrounding air rather efficiently. So you will need to have a separate indoor space from your living space or go for an outdoor pond but keep it shaded and remember it is now a greater cost for heating or cooling, especially depending on where you live, and must be done year round as this is not a koi pond. They need mid 70sF to low 80sF. I dont believe any geographical location sees those temps night and day for more than a few weeks I would imagine. Personally in the Sonarn Desert our short winters can be as low as high 30sF in the day to mid 20sF at night for a few weeks out of the year and as high as 115F during the day and 90sF at night. So in my case both heating and cooling systems have to be utilized. But dont let this scare you. It can be done and at a reasonable price just do ample research and do as much as you can yourself and you will have a gorgeous pet for years to come( oh yeah this is a longer commitment then your cat or dog) and well worth it in my opinion as you take pride in providing this animal with what it needs to live a healthy life where many have failed for one reason or another, they are a wonderful unique conversation subject and mine anyways is really just my big water puppy. They may seem stand offish or shy but that’s only because they prefer to be more nocturnal. They are very smart and they do learn and remember. If you are getting one you will not be disappointed with your experience interacting with your RTC. Sorry that was lengthy I hope sharing my experience might help at least one person in some way.

  14. I bought one at the local pet store it was very small I’ve had it a month it’s more than tripled its size I was told it would only grow to be 7 or 8 inches long it’s already around 5 I have a decent good sized tank he has plenty of room as of now and t grow but the pet store should have done there homework on this one this article helps out a lot

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