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How to Take Care of the Red tail Catfish (RTC)


The red tail catfish (RTC) is a freshwater fish that can grow very large and very fast. They are one of the most interesting members of the catfish family. In the wild, these fish inhabit large rivers, streams, and lakes. They are native to the Amazon and the great waters throughout South America

Redtail catfish are not suitable for most home aquariums because of their size, but they are still sold in fish stores and fish markets. In this article, we will provide all the information you need about caring for RTC fish.

The redtail catfish belongs to the genus Phractocephalus and is the only known remaining species of that genus. They are also known as flat-nosed catfish, antenna catfish, and banana catfish.

RTC originates from the rivers of South America and the Amazon and can be found in Brazil, Peru, Venezuela, Colombia and other neighboring countries. They have long life and can live more than 15 years if cared for properly.

Despite their initial small size (about 5 cm), the RTC will quickly grow too large for most home aquariums and may need to be moved to a pond. So before we continue, if you’re not sure that you can care for a fish this big for the rest of its life, we suggest you stay away from this fish.

RTCs are mostly maintained by professional and experienced aquarists.



Redtail catfish are large and colorful. They have long whiskers (i.e. barbels) in their mouths and a beautiful red tail. The fish are mostly dark grey/brown along their upper side with small scattered dark spots and a wavy white band of off-white running down both sides of their body.

The body is cylindrical in shape with a flat belly and a tail that is flattened laterally. The upper dorsal and caudal fins are red-orange and bear three pairs of long barbels; two on the lower jaw and one on the upper jaw.

Size and growth

When juvenile RTC fish are sold in ornamental fish stores, they are usually only about 5 cm long. You may be told by the seller that this fish will only grow to 30 cm in your tank. This is not true. The myth that a fish will only grow to the size of its tank is utterly misleading.

These fish can easily grow 2.5 cm a week when they are young; most of them reach 60 cm in a year. They can then reach over 1.2 meters in length in the home aquarium, and if left in the wild they will grow even larger.

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The largest redtail catfish on record was found in the Amazon River in 2010, and was up to 1.6 meters long and weighed 55 kg.

RTC Food

Redtail Catfish are not picky eaters. In fact, they will eat anything that fits in their mouth. They are omnivores but prefer food containing meat. Ideally, an RTC’s diet should consist of sinking carnivore pellets, fish and meat scraps, shrimp, crayfish and worms. You can also make your own food to ensure they get the best nutritional intake.

While you’ve probably seen videos of RTC eating live fish (feeders) on YouTube, it’s really not necessary. Feeders are often grown in unsuitable and overcrowded conditions which causes many problems, one of which is that they contain little or no nutritional value. Feeders can also carry diseases and parasites that can infect RTC. In addition, feeders are more expensive than other alternatives which are healthier and more nutritious.

Overeating is a common problem among this species. Redtail catfish become very sluggish after each meal and take time to properly digest their food. Juveniles should be fed daily, but when they mature they will only need one large meal per week.

Once you get to know these fish, you can watch for signs when they are sluggish. You will see when they become active again and know when to feed them. They can be trained to eat from their owner’s hand (hand-feeding).

RTC fish will eat anything that fits in their mouth, even if it’s not food. They will eat gravel, rocks, filter parts, and basically anything that is loose. We will cover this in the aquarium requirements section.

Behavior and tankmates

A juvenile catfish can be very shy. Some suggestions to help them overcome shyness are providing a cave area for them to hide in and putting the tank in a place where you usually spend a lot of time so they will get used to interacting with you.

Ideally you should keep the Redtail Catfish alone. If you really want a tankmate or tankmate, make sure that anything you put in them doesn’t get into their mouths. RTC can easily eat anything half their size, and will even eat food larger than half their size – this can be fatal as they may choke.

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The RTC is a natural predator that will attack and eat smaller fish. So any fish that is smaller than them is not a suitable tank mate. Aquarium mates should be the same size; suitable fish include gar, stingrays, and datz. Better to mix them all from childhood.

You can house RTC together, the chances of them breeding in the home tank are very low, but you should also know that there are no special sex-distinguishing traits for them in the juvenile stage.

Aquarium requirements

The redtail catfish requires a large tank. It is best to buy this fish only when you have a large tank. Initially, this fish is still small when you buy it, but the RTC will quickly grow big and make you a lot of trouble. There is much debate about the ideal tank size that this species accepts.

Some aquarists recommend a minimum of 3750 liters for this fish, which makes the tank at least 3.6 x 1.2 x 0.9 meters in size, even this size is not suitable for a fully grown adult RTC. Many people choose indoor ponds for this species which is a more appropriate solution.

We mentioned earlier that this species will eat anything that fits into its mouth, so they need a spacious tank. Avoid loose decorations, gravel or anything else in your tank.

As for the substrate, they can eat rocks and gravel so ideally, you should have a plain bottom tank. But if you don’t like the look of a bare aquarium, you can use a layer of sand. Remember that bare-bottomed tanks are easier to clean.

The redtail catfish is a fish that lives in the middle to lower levels of the tank and prefers low light. They usually live in tropical environments, so the tank conditions should suit this. The water should be between 20 and 26 ºC. You need a heater if you live in a cold area. You also have to keep the pH stable at 6.0 and 7.5.

Given the size of the tank, you will have a hard time finding an effective traditional filter so a sump filter is the best option. Sump filters on the market tend to be very expensive, so you can try to make your own at home.

So, those are the things you need to know about the redtail catfish or RTC. This fish requires a large living space and good care. If you can do that, the RTC will be your favorite fish in the house.

Nooru Ariyoushi

Nooru Ariyoushi

Nooruariyoushi has been a fish hobbyist for 20 years and is now a blog writer sharing information about fish and how to care for them.


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