Flagtail catfish Care Guide: Diet, Tank Mates, Diseases, Breeding & More

Updated: October 23, 2022

The Flagtail Catfish is a freshwater fish that is native to South America. It is a popular fish in the aquarium trade and is known for its long, flowing tail.

This fish is a peaceful community fish that does well in schools. It is an active fish that requires a lot of space to swim. It is a hardy fish that is easy to care for.

The Flagtail Catfish is a carnivore and requires a diet that is high in protein. It should be fed a variety of live, frozen, and freeze-dried foods.

This fish grows to a length of 24 inches (61 cm) and should be kept in an aquarium that is at least 125 gallons.

The Flagtail Catfish is a peaceful community fish that does well in schools. It is an active fish that requires a lot of space to swim. It is a hardy fish that is easy to care for.

The Flagtail Catfish is a carnivore and requires a diet that is high in protein. It should be fed a variety of live, frozen, and freeze-dried foods.

This fish grows to a length of 24 inches (61 cm) and should be kept in an aquarium that is at least 125 gallons.

Species overview

The flagtail catfish (scientific name: Pterodoras granulosus) is a freshwater fish that is native to South America. These fish are most commonly found in the Amazon Basin, specifically in the countries of Peru, Bolivia, and Brazil.

The flagtail catfish is a bottom-dweller and can be found in a wide variety of habitats including rivers, lakes, and ponds. They prefer areas with soft substrates such as sand or mud and plenty of hiding places.

Due to their peaceful nature, flagtail catfish are a popular choice for community tanks. They get along well with other fish and can be a great addition to any freshwater setup.

One of the most notable features of the flagtail catfish is their long, flowing tail. This is what gives them their common name and is one of the main reasons they are so popular among aquarium enthusiasts.


Flagtail catfish

The Flagtail catfish is an easily identifiable fish due to its long and colorful body. The base color of this fish is a bluish-gray. However, there are a few other colors that stand out as well.

Starting at the head of the fish and running down its back is a black stripe. This stripe is bordered on each side by a thin yellow line. Just below the black stripe is a much wider stripe of electric blue.

The electric blue stripe is also bordered on each side by a thin yellow line. This pattern continues down the entire length of the fish.

The fins on the Flagtail catfish are mostly clear with a slight yellow tinge. The dorsal fin is tall and thin and starts about halfway back on the fish. The anal fin is a bit shorter and thinner and starts closer to the tail.

The caudal fin is forked and symmetrical. The pectoral fins are a bit shorter than the dorsal and anal fins.

All of the fins have a thin yellow line running along the edges.


The average lifespan of flagtail catfish is 10 to 15 years. However, there are many factors that can impact their lifespan, such as water quality, diet, and stress.

One of the biggest threats to flagtail catfish is poor water quality. These fish are very sensitive to ammonia and nitrites, so it’s important to keep levels in your tank low.

A good diet is also important for the health of your flagtail catfish. Make sure to give them a variety of food, including live, frozen, and dry foods.

Finally, flagtail catfish are very sensitive to stress. It’s important to choose tank mates carefully and to avoid any sudden changes in the tank.


Flagtail catfish can reach a length of about 20 inches, but are typically between 12 and 16 inches long. They are a relatively stocky fish, so they don’t require a ton of space to move around.


Tank Size

The recommended minimum tank size for flagtail catfish is 20 gallons. If you’re planning on keeping a school of flagtail catfish, you should add an additional 2 to 4 gallons of tank space for each fish.

As with most fish, a larger tank is always better for flagtail catfish. If you have the space and budget for a 30 or 40 gallon tank, we recommend going that route.

Water Parameters

The flagtail catfish is a freshwater species that’s native to South America. In the wild, they’re found in a variety of habitats. But they seem to prefer slow-moving rivers and floodplains with plenty of vegetation.

This is a relatively large catfish that can reach lengths of up to two feet. So, you’ll need a sizable aquarium to accommodate them. A 75-gallon tank is a good starting point.

As for water parameters, the flagtail catfish is a bit more demanding than some other freshwater species. They prefer slightly warmer water with a neutral to slightly acidic pH.

The water should also be well-oxygenated and have a moderate flow. This can be accomplished with a quality filter and air stone.

Here are a few basic water parameters to help create a healthy flagtail catfish environment.

  • Water temperature: 75 to 82 degrees Fahrenheit
  • pH levels: 6.5 to 7.5
  • Water hardness: 5 to 15 dGH
  • Alkalinity Levels: 4-8 dKH

What To Put In Their Tank

Flagtail catfish are a species of fish that come from slow moving rivers and streams. Because of this, they’re not too particular about the conditions of their habitat.

The interior of their tank can be as simple or complex as you want it to be. We recommend something on the simpler side though since these fish are more interested in hiding than anything else.

A few pieces of driftwood or some rocks arranged in a way that provides hiding spots is more than enough. These fish like to have a lot of places to hide so don’t skimp on this!

The substrate can be whatever you want. Gravel is always a solid choice, but sand is a bit nicer for these fish since they spend a lot of time at the bottom of the tank.

Plants are a bit of a hit or miss with this species. Some aquarists have success keeping them in a heavily planted tank, but others have their plants uprooted constantly. If you want to give it a shot we recommend going with something that can handle a little abuse (like java moss or water wisteria).

Common Diseases

Flagtail catfish are actually quite hardy fish. They’re not immune to disease, but they’re not as susceptible as some other freshwater species.

The most common disease that these fish experience is ich. This is a parasite that will attach itself to your fish and cause white spots to form on their body.

While ich is fairly easy to treat, it can be quite serious if it’s left untreated. If you notice any white spots on your fish, it’s important to act fast and begin treatment immediately.

Other potential diseases include bacterial infections, fungal infections, and various parasites. These are all fairly common in the fish world but they’re not as common in flagtail catfish.

As always, the best way to prevent your fish from getting sick is to maintain a clean and stable habitat. A well-maintained tank with high-quality water conditions will go a long way in keeping your fish healthy and disease-free.

Behavior & Temperament

The flagtail catfish is a relatively peaceful fish that can get along with most other aquarium dwellers. These fish are native to South America, where they live in freshwater rivers and streams.

In the wild, flagtail catfish are schoolers. They live in groups of 10 or more fish, but they can also survive alone. In aquariums, they should be kept in groups of at least five fish. This will make them feel more comfortable and help reduce their stress levels.

Flagtail catfish are relatively shy fish, so they do best in aquariums with plenty of hiding places. They like to spend their time near the bottom of the tank, where they can find food and stay out of the way of other fish.

These fish are not aggressive and usually get along well with other fish. However, they can be territorial with fish of the same species. If you keep more than one flagtail catfish in your aquarium, make sure there is plenty of space for them to spread out.

Tank Mates

There are a few things to consider when choosing tank mates for flagtail catfish. First, these fish are on the large size. They can grow up to 2 feet long in some cases!

This means that you need to be careful about choosing fish that are too small. The flagtail catfish might see them as food.

Secondly, these fish come from slow-moving waters in South America. This means that they’re not used to a lot of activity in the water.

As a result, it’s best to choose tank mates that are also on the mellow side. Finally, flagtail catfish are bottom-dwellers.

They like to stay near the substrate where they can hide if they need to. This means that you can add fish that occupy other parts of the water column.

Some good tank mates for flagtail catfish include:

  • Plecostomus
  • Corydoras
  • Synodontis
  • Loricariids
  • Knifefish
  • Gouramis
  • Tetras
  • Rainbows


The Flagtail catfish isn’t the easiest species to breed but it can be done with some patience and the right setup.

First, you need to identify the males and females. Males are larger with more colorful fins. They also have longer ventral fins.

Next, you need to set up a breeding tank. It should be at least 50 gallons and have plenty of hiding places. The water should be fairly shallow (around 12 inches) and have a lot of vegetation.

The key to successful breeding is to make the fish comfortable. If they feel stressed they won’t breed.

Once the tank is set up, add a group of 5-6 fish. Make sure there are more females than males.

The next step is to trigger spawning. The easiest way to do that is to lower the water level by a few inches. You can also raise the temperature a few degrees.

When the fish are ready to spawn, you’ll see the female lay her eggs on the vegetation. The male will then fertilize them.

Once the eggs are laid, remove the adults from the tank. The eggs will hatch in about a week.

Once the fry have hatched, you can feed them live foods like brine shrimp or bloodworms. You can also give them crushed-up flakes.

As they grow, you can slowly introduce them to larger foods.


The Flagtail catfish is a great addition to any freshwater tank. They’re relatively easy to care for, have a beautiful appearance, and are peaceful community fish.

We do want to reiterate that they do require a bit more care than some of the other fish on this list. But, we think they’re worth it!

If you’re looking for a fish that will add some beauty and interest to your tank, the Flagtail catfish is a great option.