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…


  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?


  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!

  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.

  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.

      • 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

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