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Flagtail Catfish Care | A Peaceful And Small Catfish |

The flagtail catfish is a medium-sized freshwater fish that is famous among aquarists, and even beginners due to its peaceful temperament and ease of care.

They have slender and flat bodies. The base color of their body is gray to brown. The upper half of the body is covered with small black spots, while the lower half is silvery.

The most distinguishing characteristic of this species is its caudal fin which is strikingly marked with horizontal black and white stripes. They have the ability to tilt their eyes. Sometimes this is mistaken for blinking their eyes.

Flagtail Catfish

They have a special ability to breathe air intestinally. 

They belong to the family Callichthyidae and the genus of Dianema. There are only two species currently under the Genus of Dianema.

The name “Dianema” arises from Greek words and it stands for “two filaments” that are found near their face. The Flagtail catfish is scientifically named Dianema urostriatum.

Although the exact number of existing members of this species is not evaluated, they are not a threatened group. They are listed under the  “Least concern” group in IUCN.

The native land of the Flagtail catfish is the Brazilian Amazon basin which gives shelter for a number of species.

The Flagtail catfish are widespread in the creeks, tributaries and floodplains of the Amazon basin.

How big do Flagtail catfish get?

They are not large fish and they can reach 4.9 inches (12.5 cm) upon their maturity.       

Is Flagtail catfish aggressive?

No, they are very peaceful fish.

Flagtail catfish behavior

They are very peaceful fish species and a good suit for community tanks. Unlike many other aquarium fish, they do not harm even the smallest tankmates.

However, make sure not to add tiny fry because the Flagtail catfish may eat them misunderstanding foods.  

They are totally non-aggressive towards the same species. Although you can put a single specimen in a community tank, many aquarists suggest putting a group of 3-6 individuals.

This is because they tend to be active when there are many individuals of the same species. Though catfish rarely swim like shoals, you can see small groups of Flagtail catfish swim like shoals too.

Unlike most other catfish species, Flagtail catfish prefer to dwell in the shady vegetated and sandy substrate at the bottom. They are medium-paced swimmers in captivity but they swim fast during the feeding time. 

How long do Flagtail catfish live?

The average lifespan of a flagtail catfish extends up to 10 years in aquariums. 

Their lifespan in their natural environment tends to be shorter because they may be prayed for by predators.

One look Care guide

Scientific nameDianema urostriatum
Common nameFlagtail catfish
Care levelEasy 
Native toAmazon, South Africa 
Type Freshwater fish
Color Silver, Black and white 
Tank size20 gallons for one fish 
Prefered temperature77-82 F (25-28 C)
Other water parameters (ammonia ,ect)pH: 6.0-8.0Hardness : 5-20°H
Prefered salinityFreshwater fish 
Size4.9 inches (12.5 cm)
Growth rateMedium 
Temperament Peaceful
Recommended tank matesBleeding Heart Tetras
Black Widow Tetras
medium-sized Rasbora species
Corydoras catfish
medium-sized Loricariids 
Preferred foodBrine shrimp,
Mosquito larvae and
Some aquatic plants,
Commercial foods (pellets, frozen foods )
Feeding frequencyFew times per day 
breedingBubble nesting, Hard to breed in captivity

Flagtail catfish care

Flagtail catfish size

They can reach a length of 4.9 inches (12.5 cm)

Flagtail catfish tank size

20-gallon size is enough for one specimen. But on many occasions, they are kept as a small group and for small groups of 4-6 members, 140 liters tank 48″ x 15″ x 12″ (120cm x 37.5cm x 30cm)  is recommended.

How many Flagtail catfish should be kept together?

They are peaceful species and you can keep small groups of fish together. Aquarists suggest 3-6 individuals are best for a community tank.

Tank setup

They adapt well in artificial tanks and aquariums and all you need to do is to provide them with relevant water parameters and tank conditions. 

The Flagtail catfish dwells in the shallow waters of rivers and lakes near the sandy substrate. A biotope tank with a sandy substrate is suitable for the Flagtail catfish because they love to dig the substrate.

You can add tangles of driftwoods and roots to mimic their natural environment. Some aquarists suggest adding dried oak and beech leaves to further enhance the natural look of the tank, but make sure they are free of parasites when you add them. 

They are happy with plenty of hiding places and putting bogwood, rocks , robust planting and leaf litter is good. As they are substrate diggers make sure your decorations are secured. 

They used to live in slow-moving waters in their natural environment and hence water movement of the aquarium need not be vigorous. However, they need clean water and efficient filtration should be installed. 

They are nocturnal animals and do not prefer bright light. It is good to provide them with dim light.

You can even use bright light if it is diffused and scattered with floating plant species. If you need to see them in the late evening, using blue moonlight is highly recommended.

Since they can breathe air, keep some open space between the aquarium lid and water level for respiration.

The flagtail catfish is regarded as a particularly sensitive species and needs to keep the tank conditions at their best. 

Water quality condition

Flagtail catfish are sensitive to the build-up of organic wastes and therefore make sure to keep good water conditions.

They grow well under warm temperature conditions as their natural environment is the Amazon where the temperature is high.

The temperature should be in the range of 77-82 F (25-28 C).    The ideal water pH required for their survival and breeding is between pH 6.0-8.0. The Hardness should be in the range of 5-20°H.

Flagtail catfish breeding 

Flagtail catfish male or female identification

It is not easy to identify the female and male Flagtail catfish at a glance. However, they show sexual dimorphism and you can differentiate between them with proper investigation.

The males have slightly thickened leading to few rays of the pectoral fins. Apart from this, mature females are likely to be rounder in the body than males.

Flagtail catfish breeding

There are only a few details on Flagtail catfish captivity breeding. They are a bubble nesting fish. However, there is some conflicting information such as they lay eggs in pits excavated from the substrate. 

Condition the fish

If you have an idea to breed them first, your fish should be conditioned for it. Feed your targeted fish with plenty of live foods and high-protein frozen foods.

Stimulate the breeding

Breeding can be stimulated by the replication of wet and dry seasons in the aquarium. They breed at the onset of the wet season.

First, lower the water level of the tank and increase the water temperature by a few degrees to simulate the dry season.

Some aquarists suggest removing the filter and letting the hardness of the water rise a few numbers.

Both the organic compounds and dissolved salts increase during the dry season because of the low water amount in their natural environment. 

After a few weeks, you can simulate the wet season by increasing the water level using cooler water and begin to feed the fish heavily.

Most of the fish will begin to spawn at this point. There are still some reasons they are not ready for breeding such as barometric pressure and time of year. 

Add nesting materials

When they reach maturity, add a piece of polystyrene or plastic lid of some kind to float at the surface and provide a potential nest-building site.

Many aquarists suggest using a yellow-colored object is better. Secure the object in one place. The males fertilize a maximum of three to four eggs on the pelvis of the females for about 30 seconds.

After the females attach their extremely sticky eggs beneath the plastic lid. At this time remove the adults from the tank as they might eat the eggs.  You can feed the fry with nauplii and /or microworm.

Compatibility between a male and female catfish stays strong until 100 eggs have been laid during the time of breeding. They spawn in the upstream section in the open water conditions of the rivers.

Flagtail catfish fry care

You can use a separate tank for the Flagtail catfish fry until they come to considerable length.

The most suitable feed for the fry are nauplii and the microworm. Other than the above, there are no special care instructions for the fry. 

Special tips

Flagtail catfish have hardened pectoral fins that are sharp enough to pierce even the human skin. Therefore, make sure to take enough precautions before handling them.

Use hand gloves and plastic containers to move them. You should not use a net. Because the spines may get entangled in the mesh and the fish may get injured. 

The Flagtail catfish are scaleless fish species. Therefore, they are extremely sensitive to salt. Make sure to keep the salinity of the water at the recommended range.

In addition, the decorations such as rocks and driftwoods should not carry sharp edges as they may get injured easily as they have no scales to protect themselves.

Many articles stated that the base of each spine of Flagtail catfish has axillary glands that have mildly toxic secretions.

Although , there is no clue that this toxic secretion harms humans other than mild irritations on skin, be careful enough when you handle them. 

Since almost all the Flagtail fish in the trade are wild-caught, they may carry pathogens in their skins.

Therefore, you should take necessary precautions to avoid other tank members getting infected by the pathogens.

Feeding behavior of Flagtail catfish 

What do they eat ( in the wild and in an aquarium)

Flagtail catfish have an omnivorous diet. They feed on almost any meal that fits their mouths when they are in the wild.

Brine shrimp, bloodworms, mosquito larvae and some aquatic plants are some of their favorite meals. They feed on sinking frozen foods like mosquito larvae, chopped krill, brine shrimps, and earthworms in the aquarium.

They are enthusiastic feeders and can adjust quickly to commercial foods.

You can train them to eat good quality dried food such as flake or pellets alongside frozen or freeze-dried foods.

As they are omnivores, include some vegetable matter in the form of blanched courgette, spinach and cucumber occasionally to make their food balanced.

Keep in mind the Flagtail catfish are very greedy and boisterous at feeding times. The other fish species in the community tank may not get meals due to this behavior.

Therefore, spread the fish feed at several locations within the tank simultaneously and so that the other species also have a chance to get the food. 

If you have nervous species in the tank, observe carefully whether they get enough food. 

How often should you feed

As they are enthusiastic feeders, it is better to feed them a few times per day. Make sure you feed online the amount that they can eat within a couple of minutes, other than the remaining food affects the water quality of the aquarium in a bad way.

When should you feed (time of the day)

As these fish are nocturnal, it is best to feed them when the lights are out. However, you can train them to accept food during the daytime also. This may take some time. And you have to wait until they get used to the tank conditions. 

How long they can go without food

They are enthusiastic eaters and can’t go a long time without food

What fish can live with Flagtail catfish?

Flagtail catfish are peaceful species and they can live with many fish species.  

Typical tank mates could include medium-sized or deep-bodied characins. Possible tankmates are Bleeding Heart Tetras, Black Widow Tetras, etc, Rainbowfish, medium-sized Rasbora species, Corydoras catfish, and medium-sized Loricariids (suckermouth catfish), and more. 

Is Flagtail catfish aggressive?

They are not aggressive. Instead, they are very peaceful species that can live with many fish species.

Can Flagtail catfish live in a pond?

Yes, technically there is no issue to keep them in a pond. 

Credit to : PlanetCatfish TV
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About Dr.Chamika

Hello, I'm Dr. Chamika. I am a Researcher in Water quality, Aquatic organisms, and Environmental chemistry. I am a passionate fish keeper, with10 years of experience. My mission is to help other aquarists experience the joy of fish keeping.