November 21

Sarah Robertson

Flagtail Porthole Catfish: a Guide to Caring for Your New Fish Friend

The Flagtail Porthole Catfish (striped tail catfish) is a tropical freshwater fish belonging to the Callichthyinae sub-family of the family Callichthyidae. Amazon Basin in South America is the native home of this fish. The Flagtail Porthole Catfish is found in slow-moving tributaries and backwaters, as well as streams, lakes, and ponds.

The Flagtail Porthole Catfish is a great bottom-dweller for bigger tanks with medium-sized tankmates. Because of their highly sociable nature, they are best kept in groups of five or more.

There should be a soft sand base with plenty of shaded hiding places, as well as bogwood, rocks, firm vegetation, and leaf litter in their tank. These catfish are strong diggers, so make sure that all structures are safe. Water filtration should be effective, yet water movement may not need to be too vigorous.

Preferably, low-level lighting is used; however, brighter illumination may be utilized if it is dispersed with floating plant species, and the use of a blue moon light is strongly suggested for looking at this nocturnal species after sunset.

To learn more about keeping Flagtail Porthole Catfish, read on!

Quick Facts about Flagtail Porthole Catfish 

  • Scientific Name: Dianema urostriatum (Miranda Ribeiro, 1912)
  • Family: Callichthyidae
  • Common Names: Flag Tail Hoplo, Flag Tail Porthole Catfish, Schwielenwels (Germany), Flagtail Catfish, Halestribet Pansermalle (Denmark).
  • Distribution: Amazon River basin, Brazil.
  • Maximum Size: 84mm or 3.3inches (8.4 cm)
  • Sexual Dimorphism: Mature males possess thickened leading pectoral fin rays. Mature females fuller bodied.
  • Temperature: 25.0-28.0°C or 77-82.4°F
  • PH: 6 to 8.0
  • DH: 5-19°
  • Min Tank Size: 24 inches 20 Gallon.
  • Diet: Omnivorous, Will take a variety of prepared foods, flake, frozen and live.
  • Behavior: Peaceful, somewhat timid.
  • Care: Moderate, due to its’ shyness. Can be hard to acclimate.
  • Communities: Good
  • Water Parameters: Will acclimatize to a wide range of conditions. pH: 6.0-7.8, dH: up to 20 degrees.
  • Compatibility: Community of medium-sized fish
  • Lighting: Low

Flagtail Porthole Catfish Care 

Flagtail Porthole Catfish need to have a regular maintenance and water change schedule, as they are vulnerable to the accumulation of organic waste. Flagtail Porthole Catfish can be excessively loud while feeding, therefore make sure to feed the fish at multiple locations in the tank at the same time to ensure that the other fish in the tank are getting enough food.

As with all fish, Flagtail Porthole Catfish need a balanced diet that includes both plant and animal matter. A good quality flake food or pellet can be the basis of their diet, but should be supplemented with live, frozen, or freeze-dried foods such as bloodworms, brine shrimp, and daphnia. To ensure good health, it is also important to offer a variety of vegetables such as blanched spinach, zucchini, and peas.

The Flagtail Porthole Catfish is a particularly delicate species, so acclimatize to the aquarium gradually and cautiously. These catfish have the capacity to breathe air via their intestines, and a tiny space should be kept between the surface of the water and the cover slides so that the fish can swim up to the surface and obtain air.

They can do this several times each day. If the water quality in the aquarium is not good, or if the fish are stressed for any reason, they will stop feeding and may quickly succumb to illness.

All you need is a 20-gallon freshwater aquarium, dim lighting, and lots of hiding places for their optimum care. Maintaining proper water conditions for Flagtail Porthole Catfish is critical for their long-term health. Weekly water changes of 20% are also recommended to keep the tank clean and the fish healthy.

Flagtail Porthole Catfish Size

The average Flagtail Porthole Catfish size is around 3-4 inches (8-10 cm). However, most specimens have been known to reach up to 3.3 inches (8.4 cm). The major factors in determining the size of a Flagtail Porthole Catfish are age, diet, and water conditions. If you provide your fish with a good diet and proper water conditions, they can reach their maximum size..

Flagtail Porthole Catfish Lifespan 

The average lifespan of a Flagtail Porthole Catfish is between 5 and 8 years, although some have been known to live up to 10 years in captivity. The key to a long and healthy life for your Flagtail Porthole Catfish is to provide them with a good diet, regular maintenance and water changes, and to avoid stress.

Flagtail Porthole Catfish Appearance

Flagtail Porthole Catfish Appearance 

The tail fins of the Flagtail Porthole Catfish have horizontal black and white alternating stripes, whereas the only other member of the species has a transparent caudal fin and is generally smaller.

The flagtail porthole catfish is a distinct type of armored catfish with a distinctive black and white barred tail and spotted pattern and this is what distinguish it from all other members of the Loricariidae family.

They grow to a length of 3.3 inches. Since they are small fish, they do not require a large tank. A 20-gallon tank is sufficient for a small group of these fish.

Sexual Dimorphism 

In males, the leading few rays of the pectoral fins are somewhat thickened. Rounder bodies are more typical in mature females than males. It is easy to identify their gender during breeding season as the males will have a more defined genital papilla.

Flagtail Porthole Catfish Behavior

Flagtail Porthole Catfish are very peaceful fish that is suitable for a community tank. They are nocturnal fish that spend most of the day hiding in caves or behind rocks and plants. At night, they become active and will often swim out in the open looking for food. It is not harmful to even the tiniest of tankmates, but tiny fry may be hoovered up.

It is non-dominant and non-threatening towards conspecifics. While it can be kept as a single specimen if desired, a small group of three to six fish will make the creature far more sociable and active. When you maintain a catfish in this manner, it will occasionally swim in a shoal in midwater. It is also less likely to be intimidated and will not cower in a corner if there are other fish in the immediate vicinity.

Flagtail Porthole Catfish Feeding & Diet 

The diet of a Flagtail Catfish is simple to maintain since it will consume a wide range of foods. Offer your catfish a varied food composed of dried sinking pellets, tiny live and frozen foods. It may consume from the surface once it's been established. They'll soon get used to their aquarium conditions and will start eating both from the water's surface and from the bottom. It is best to feed them a varied diet consisting of:

  • Meaty foods like bloodworms, chopped earth worms, brine shrimp
  • Quality flake
  • Frozen or freeze-dried foods

They should also be given some vegetable matter, such as a staple flake or sinking pellet diet. To determine the best long-term feeding frequency, feed them every few hours what they'll eat in a few minutes and then monitor their girth and growth rate over time. Don't forget to remove any uneaten food as it can lead to pollution and health problems.

Flagtail Porthole Catfish Tank Mates 

The peaceful fish are great bottom-dweller for bigger tanks with medium-sized tankmates, and they're best kept in groups of five or more due to their extremely social behavior. Medium-sized or deep-bodied characins are good tankmates.

Ideal tankmates for flagtail porthole catfish include:

  • Peaceful cichlids
  • Gouramis
  • Bleeding Heart Tetras
  • Black Widow Tetras
  • Rainbowfish
  • Guppies
  • Loaches
  • Mollies
  • Medium-sized Rasbora species
  • Corydoras catfish
  • Platies
  • Small & Medium-sized Loricariids (suckermouth catfish)

It is not particularly well-suited for a community of larger or more aggressive species, but it is somewhat more robust than its relative D. Longibarbis.

Aggressive and territorial tankmates are to be avoided, as they may bully or outcompete the flagtail porthole catfish for food.

Some bad tankmates for flagtail porthole catfish are:

  • Large cichlids
  • Piranha
  • Arowana
  • Oscar Fish
  • Flowerhorn
  • Tiger Barb
  • Betta fish

When kept with the appropriate tankmates, flagtail porthole catfish are very social fish that love to shoal together. So choose tankmates that will allow your fish to feel comfortable and secure in their environment.

Flagtail Porthole Catfish Tank Setup

Flagtail Porthole Catfish Tank Setup 

The Flagtail Catfish is adaptable, but it will thrive in aquariums that are intended to replicate its natural Amazonian habitat. Good tank design options for this species should include the following:

Tank Size

A 20-gallon long aquarium is a good minimum size for these fish, but the larger the tank the better.

Water Parameters

Maintaining ideal water parameters is critical for the health of your flagtail catfish. So their tank should have a Temperature between 77-82 degrees Fahrenheit, a pH level of 6.0-8.0, and hardness between 5-19 dGH.


A sandy or smooth pebble substrate is best for this species as it will help to keep their barbels clean and free from debris.


It is important to provide plenty of hiding places and retreats for your flagtail catfish. Driftwood, rocks, and plants all make good options. Just be sure that any decorations you use are safe for aquarium use and won't damage your fish.


Specialized filtration systems are not required for Flagtail Porthole Catfish, though they can be maintained with high-end power filters, canister filters without difficulty.

The Flagtail Catfish prefers moderate water flow and does not require any special lighting. The Flagtail is a small fish species that will be more at ease in an aquarium with lots of foliage, which will provide it a feeling of security if it feels endangered.

The addition of a few handfuls of dried oak or beech leaves scattered over the base of the tank may be used to approximate its habitat. It does well in a variety of settings, as long as there is enough of shelter. Tanks that have been heavily planted are particularly desirable.

Flagtail Porthole Catfish Breeding 

This species would make an excellent hobbyist breeding project. The fish should be conditioned with a variety of live and frozen foods high in protein. It is claimed that the fish may be enticed to reproduce by mimicking wet and dry seasons in the aquarium. It's reportedly a bubble nest builder, but some conflicting information exists claiming that the eggs are deposited in pits dug from the ground.

If you wish to breed these, start with a small group of four to six fish. Place a small piece of poystyrene or other sort of floating lid in the water to act as a nest-building site and offer something for the female to build on top of. Ideally, the object should be kept in one place.

Apparently, a lot of live food and frequent large water changes are essential to get the fish into condition. If you discover eggs, it's a good idea to remove the adults because they might eat them. Once their yolk sacs have been absorbed, the fry should be large enough to consume Artemia nauplii and/or microworm.

If you're having trouble getting a spawn, consider simulating the dry and wet seasons seen in its natural habitat. The fish breed during the rainy season, so first decrease the water level in the tank, raise the temperature by a few degrees, and starve the fish for a few weeks to resemble the dry season.

 If you wanted to truly go all out, you might also remove the filter (use another tank to keep it mature) and make the water somewhat harder. The dry season, on the other hand, is associated with an increase in both organic chemicals and dissolved salts. This is simply because there isn't as much water around to dissolve them.

After a few weeks, add colder water to the tank and begin feeding the fish more frequently. If you removed the filter, fill it with water and replace it. If the water's hardness has increased, use very soft (preferably ro) water to top up. In the extreme case where the fish continues to refuse to spawn, keep in mind that many South American species' breeding activity is influenced by such factors as barometric pressure and season. Because the rainy season varies depending on location, it's possible that certain species only reproduce during these months.

Also, bear in mind that these fish are very sensitive to changes and that any new addition (including a new filter) can easily disrupt the spawning process.

Flagtail Porthole Catfish Fry 

To care for the fry, it is best to remove them to a separate tank. The fry are very small and need tiny food. Baby brine shrimp or infusoria are ideal. With good care, the fry will grow quickly. Once they are large enough, they can be returned to the main tank. Do not overfeed the fry, as this can cause problems with their digestive systems. It is best to feed them small amounts several times a day.

The fry are very sensitive to changes in water quality, so be sure to do regular water changes and keep an eye on the ammonia and nitrite levels. The fry are also very sensitive to light, so it is best to keep the tank in a dimly lit area or cover the tank with a dark cloth. As the fry grow, they will start to show their colors.

Flagtail Porthole Catfish Diseases

Flagtail Porthole Catfish Diseases 

Flagtail porthole catfish are relatively disease-resistant, but they can be susceptible to infections if their environment is not clean. Some common symptoms of disease include lethargy, loss of appetite, fuzzy patches on the skin, and white spots on the fins.

If you think your fish might be sick, the first thing you should do is check the water quality. Ammonia and nitrite levels should be at 0 ppm, and nitrate levels should be below 20 ppm. If the levels are too high, do a water change and vacuum the gravel to remove any waste.

It is also important to feed your fish a varied diet of high-quality food. A nutritious diet will help them stay healthy and fight off infections.

Some common diseases that can affect flagtail porthole catfish include:

Ich: This is a viral infection that causes white spots to appear on the fish's body. The fish may also become lethargic and have trouble breathing.

Fin rot: This is a bacterial infection that causes the fins to turn black and disintegrate.

Gastrointestinal parasites(H3): These are parasites that live in the fish's intestines and can cause weight loss, vomiting, and diarrhea.

Fungus: This is a type of infection that can cause white spots or patches to form on the fish's body.

Dropsy: This is a condition that causes the fish's body to swell up with fluid. It is usually fatal.

To prevent diseases from affecting your flagtail porthole catfish, it is important to keep the tank clean and the water quality high. Be sure to do regular water changes. If you notice any signs of disease in your fish, isolate them in a hospital tank and treat them with a recommended medication. A sick fish will usually recover if it is treated early. So closely observe your fish and act quickly if you think something is wrong.


How Big Do Flagtail Catfish Get? 

Most Flagtail Catfish grow to be about 8.4cm long. However, some have been known to grow more than that. Some factors that affect how big a Flagtail Catfish can grow to be include the quality of their care, diet, and water conditions.

Can I Put More Than One Flagtail Catfish Together? 

Yes, you can put more than one Flagtail Catfish together. However, it is important to make sure that they are all around the same size. If you have fish that are different sizes, the larger fish may bully the smaller ones and prevent them from getting the food and care they need. It is best to keep them in a group of at least 6 similar-sized fish.

How Do You Take Care of an Flagtail Porthole Catfish? 

The Flagtail Porthole Catfish is a hardy fish that can be easy to care for as long as their basic needs are met. They need a tank that is at least 20 gallons, with plenty of hiding places and caves.

They should be fed a diet of live, frozen, or freeze-dried foods. It is important to do regular water changes and to keep an eye on the ammonia and nitrite levels. It is also important to choose the tankmates carefully, as some fish may bully or harass the Flagtail Porthole Catfish.

What Temperature Should Water Be at for a Flagtail Porthole Catfish? 

The ideal water temperature for a Flagtail Porthole Catfish is between 25-28 degrees Celsius. If the water gets too cold, the fish may become sluggish and have trouble feeding. If the water gets too hot, the fish may become stressed and more susceptible to disease.

What Should I Feed My Flagtail Porthole Catfish? 

Flagtail Porthole Catfish are omnivorous and will eat a variety of live, frozen, or freeze-dried foods. Some of their favorite foods include bloodworms, brine shrimp, and daphnia. It is important to feed them a varied diet to ensure that they are getting all the nutrients they need.

Final Thoughts 

The Flagtail Porthole Catfish is a robust fish that can be kept without difficulty if its basic requirements are met. They need a tank that is at least 20 gallons in size., with plenty of hiding places and caves. They should be fed a diet of live, frozen, or freeze-dried food. It is important to do regular water changes because these fish are very sensitive to changes in water quality.

Their peaceful nature and small size make them ideal candidates for a community tank. Peaceful tankmates include other small catfish, Corydoras, tetras, and livebearers. It is important to avoid putting them with larger fish or fish that are known to be aggressive, as the Flagtail Porthole Catfish may become stressed and more susceptible to disease.

With proper care, the Flagtail Porthole Catfish can be a fun and interesting addition to your aquarium. It can live up to 10 years in captivity. If you are looking for a hardy and low-maintenance fish, the Flagtail Porthole Catfish may be the perfect choice for you!

Sarah Robertson

I am a passionate blogger who also happens to be a fish keeping enthusiast. Writing about my hobby is something that I absolutely love to do, and it's no secret that my chosen topic is always centered around fish keeping.

Sarah Robertson

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