Redtail Catfish Care Guide

The redtail catfish, otherwise known as phractocephalus hemioliopterus, is a type of catfish we see that is common in aquariums. It is native to South America and is interestingly the only surviving member of its genus – catfish phractocephalus. It makes most of South America its home and can be found in South American river basins in Ecuador, Guyana, Venezuela, Colombia and more.

They are among the large aquarium fish we can see in the trade and are one of the fastest growing as well. Catfish are not known for their beauty, hence the term “catfished”, however, the phractocephalus hemioliopterus is actually considered one of the more attractive members of this family. Although the redtail catfish is often seen in the aquarium trade, it is very unsuited to tank life due to its sheer size.

Let’s take a look at how to care for this large fish and familiarize ourselves with more details about this species.

Information Chart
Care Level:
Medium to difficult
Dark brown, grey with a thick yellow/white band
15 years
3-4 feet
Minimum Tank Size:

31500-2000 gallons

68-80 ºF (20-26 ºC)
Water Conditions:
pH 6-7
Tank Mate Compatibility
Larger non-aggressive fish

Care Level

In a word, caring for the redtail catfish is difficult, which is why they are not recommended for first-time aquarists. They need a large tank due to their size and aren’t the most friendly fish in the sea. On the plus side, they are freshwater fish, which means you don’t need to pay too close attention to the salt levels in the tank.

They are resilient and can adapt to a broad range of habitats, which is why they are considered an invasive species by some. An invasive species means a species that has the power to force out other species that are native to a specific area. This resiliency is also what makes them not as sensitive to certain tank conditions.

Even though they are tough, the right environment is still required to keep them happy and healthy. In captivity, the redtail catfish won’t live as long as it could potentially in its natural habitat. Their size is again something to consider. There are many cases of redtail catfish outgrowing the aquarium at home and because the aquarist cannot accommodate it anymore, they are donated to aquariums.

If you do not have an aquarium large enough to house the redtail catfish until maturity, we would advise you to search for another species that is of a more reasonable size.

Temperament and Behavior

Fish are either peaceful or aggressive, but these catfish although many agree are aggressive, can fall somewhere in between. Redtail catfish are predatory freshwater fish. If these natural instincts kick in, then some may argue that they are quite aggressive. Factors that influence their temperament and behavior include the environment.

Your tank setup will largely dictate how your fish acts. However, the most common displays of behavior by the redtail catfish is roaming the bottom of the tank. They slowly pace around the bottom of the tank as most other catfish do. Before the catfish matures, some aquarists say that they can be quite timid. Giving them lots of places to hide can help.



How big can a red tail catfish get? As we previously mentioned, redtail catfish are quite large freshwater fish. Large enough to outgrow their initial tanks. The redtail catfish is said to be one of the more attractive catfish species with beautiful colors and, of course, a red tail. Similar to other catfish species, they also feature two barbels on their mouths.

How fast do red tail catfish grow? They grow quite quickly and to a pretty large size. You’re looking at at least an inch a week and they will be at least two feet in length in about a year. Keeping them in tanks limits their freedom of movement significantly compared to the wild, which is why they won’t grow as large in size as they would in the wild. At best, they will be about 3-4 feet long, when in the wild they may reach up to a whopping 5 feet in total!

For a fish in captivity, 3 feet is gigantic. Not only in terms of the fish, but also in the tank size. It may be hard to search for a tank large enough to house the redtail catfish in just any aquarium store. A baby phractocephalus hemioliopterus is only about 5 cm, which is why a lot of aquarists are not aware of how large they may potentially be.

Aquarists may be under the misconception that keeping the redtail catfish in captivity at a young age could limit their growth. Although this is true, they will still most definitely reach at least 3 feet long. Regardless of how much “stunting” captivity has on your redtail catfish, the tank size will still need to be astronomical.

The largest recorded retail catfish in the world is measured at 4.62 feet and weighing in at an astounding 56 kg (123 pounds 7 ounces)! If you ever see pictures of these amazing catfish, you will be amazed by how large they can be compared to the average human male.


While they can be colorful, most of them feature shades of dark brown and/or grey with spots and a thick yellow/white band that runs along the length of their torso. Aside from the tail fins, the dorsal and caudal fins also feature hues of red and orange. Similar to other catfish species, the redtail catfish also features a flat underside.

As far as sexing goes, there doesn’t seem to be distinguishing marks to help breeders and aquarists determine if the catfish is male or female.


Redtail catfish live relatively long lives. In captivity, data shows that they can live to about 15 years. It is assumed that they exceed this number in the wild due to more suitable environments. They are quite a demanding species of fish, and what they require may be difficult for aquarists to provide in home tanks. This is a factor that can shave years off its life.

To create the perfect situation for these creatures to thrive, you need to pay attention to the different subsections we have listed below. We can say for now that to give them enough space, the right food and ideal tank conditions are crucial elements for the phractocephalus hemiolipterus to thrive.

Remember that this particular catfish is native to South America, more specifically, in the river basins. This means that they are considered freshwater fish that need an aquarium with water and temperature similar to that in South America.


What do red tail catfish eat? Fish this size need to eat a lot of food, right? You’re right! Redtail catfish are big eaters and will eat just about anything. Just because that is the case, it doesn’t mean that that is what you should do. Simulating their natural diet in the tank will help prolong their lifespan. In nature, the phractocephalus hemioliopterus eats worms, other fish of a smaller size, insects and vegetation along the bottom of the river basins.

In captivity, you can also opt to feed them smaller fish and worms but substitute the others with shrimp, and some pellet food. Flakes are advised against since flakes don’t generally sink. If you opt for pellet food, you need to choose the sinking variety as that is where your redtail catfish spends most of his time.

They are omnivorous fish but prefer meats. This is why having a supply of frozen food can help satisfy their hunger. They don’t actually need to be fed much. The younger phractocephalus hemioliopterus need food every other day but full-grown redtail catfish can do well with one large meal a week.

You know when it’s time to feed them when your fish become active again. This is because the phractocephalus hemioliopterus need time to digest their food and become lethargic after feeding (sort of like you after turkey dinners). Overfeeding is an issue commonly seen among fish. It’s hard to gauge when some of species need food but consistency is key and remember that they can go a long while without food.

Can you eat a redtail catfish? This is a funny question that we are often asked. Because of their size, they are unfortunately considered game by some. However, the natives of South America don’t generally eat the meat because the fish is often dark in color.


The redtail catfish is of the primelodidae family (whiskered catfish) under the phractocephalus family in the hemioliopterus genus. They are primarily found in the South American Amazon Orinoco river basins but have now been introduced to other parts of the world, including Thailand. They can also now be seen in Florida as well.

Tank Conditions

Minimum Tank Size

As we mentioned, this catfish with a red tail is not easy to care for. If you are determined to keep one in your home, here are a few things that are absolute musts. Just knowing the tank size may put you off a bit. In order to have enough room for ONE adult redtail catfish, the tank size you are looking at is about 1500-2000 gallons. No, we did not include an extra zero.

Since they get to about 3-4 feet, this is the adequate size to keep them happy and have enough room to roam. The tank size is definitely something that you cannot compromise on. With this, many people forget about ever owning a redtail catfish because a tank this big just isn’t doable for regular people.


As mentioned, redtail catfish are very resilient and can withstand and adapt to many conditions, but getting the water conditions just right will only further benefit the phractocephalus hemioliopterus. The ideal water temperature should be between 68 to 80 degrees Fahrenheit (20-26 degrees Celsius) with pH levels sitting between 6 and 7.

Water Conditions

The water quality is among the toughest to maintain for a redtail catfish. This is due to the enormous size of the tank and the fact that they eat a lot. The more fish eats, the more waste there could possibly be. Suffice it to say, most of your time may be spent on monitoring the water conditions.

In terms of decoration and populating the tank with substrate, don’t put too much! As we mentioned, the phractocephalus hemioliopterus eat just about anything. We mean anything ranging from gravel to pieces of floating debris and even the plant substrate. So you are looking at a very large and sparse tank. This is great in a way because a tank with less in it can mean less cleanup and maintenance.

It may not look as nice as a lush green tank, but it’s what they need. Speaking of what they need, since they are bottom dwellers, place the tank in low light areas as well.

Maintenance and Care

The water conditions need to be regularly maintained. Since they are freshwater fish, you may need to pay a closer eye on the soiling of the water due to waste. River basins generally do not have a high flow rate so still waters are fine. For such a large tank, traditional filters may have a difficult time dealing with the water, so opt for a sump filter instead. Unfortunately, a good sump filter can really rack up the bill.

Since they are considered tropical (due to them originating from The South American Amazon Orinoco river basins), you may need to invest in a separate water heater if you are unable to maintain the constant warmer temperature. Since the aquarium tends to be much larger in size compared to regular tanks, it may cause your heater to work overtime and rack up the electricity bill.

They can get used to different environments and water flow rates, but what’s more important to keep an eye on would be the water temperature, tank size, and what you keep in the tank with them.

Suitable Tank Mates

Imagine a single catfish floating around with no friends in a sparse tank. The situation seems pretty bleak, but it’s okay, you can add some tank mates (on the condition that they are suitable of course). It’s tough to find the right aquarium buddies for these fish because they are large, somewhat aggressive, and will eat almost anything. The phractocephalus hemioliopterus eat smaller fish, so definitely make sure the tank mates you select are not much smaller.


Look for fish that are the same size or larger with a focus on non-aggressive temperament. Introduce your catfish to his or her new friend early on so they have time to get acquainted. To minimize trouble, those that do go ahead in keeping redtail catfish usually only keep one. Adding more creatures to the tank only adds more issues such as tank size and having to add some sort of substrate and plants to accommodate the other species can compromise your catfish.

Beautiful stingrays can be optimal tank mates. Some beautiful smaller sharks such as the iridescent shark can also hold its own against the phractocephalus hemioliopterus. Ideally though, we suggest keeping your catfish solo in a tank.


Breeding with these large fish is extremely difficult. A regular aquarium even one of 2000 gallons may not be large enough for 2 of these might catfish and this makes it tough to create the circumstances in which they mate. Even in large ponds it can be difficult for successful breeding.

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The phractocephalus hemioliopterus is quite the trophy fish to keep. It will surely attract a lot of attention to have such a majestic yet menacing predator swimming in a home aquarium. Since they are so large, an aquarist needs to be prepared for all it will take to raise these creatures in captivity. This includes the large aquarium and regular water maintenance. Since they are predatory in nature, we recommend they be kept alone.

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