Flagtail Catfish – Dianema urostriatum

Flagtail Catfish, known scientifically as Dianema urostriatum, is a peaceful, fascinating and relatively hardy species that has been gaining popularity among aquarists looking for something more original than classic tetras or livebearers. Its elegant body, attractive striped tail and unusual way of swimming make it a wonderful choice for planted community aquariums. In this article we will look at its natural environment, care requirements and compatibility with other fish, and we will also suggest how to create an ideal tank for this catfish using equipment easily available in MB Store.

Natural habitat and appearance of Flagtail Catfish

Dianema urostriatum originates from slow-flowing tributaries of the Amazon basin in South America. In nature it lives in shallow, calm waters with sandy or muddy substrates, often shaded by dense jungle vegetation. The water is usually soft, slightly acidic to neutral, rich in organic matter and filled with branches, roots and fallen leaves. Recreating these conditions in the aquarium noticeably improves the health and behavior of this catfish.

Flagtail Catfish reaches about 8–10 cm in length, which makes it a perfect inhabitant for medium-sized community tanks. The body is elongate, slightly laterally flattened, covered with two rows of bony plates characteristic of the Callichthyidae family. The coloration is generally beige to light brown with subtle darker speckles, while the caudal fin presents striking horizontal stripes, which gave rise to the English name “Flagtail”. The large, expressive eyes and delicate barbels around the mouth underline its charming, inquisitive nature, particularly visible during feeding and nighttime activity.

What distinguishes this species from many other bottom dwellers is its semi-pelagic behavior. Dianema urostriatum does not remain exclusively at the bottom like typical Corydoras; it often swims in the midwater layers, especially when kept in a group. This gives the aquarium a dynamic, busy look, as the fish actively patrol different zones, searching for food and interacting with each other. For aquarists who appreciate constant, but not chaotic, movement in the tank, Flagtail Catfish is an extremely attractive choice.

Due to its natural environment, this catfish is adapted to variable oxygen levels and sometimes turbid water, which explains its relatively high tolerance for less-than-perfect conditions. However, the goal of responsible aquarists is to provide it with stable, optimal parameters. With carefully selected filtration, proper substrate and thoughtful decoration available in MB Store, it is easy to design an aquarium in which the natural beauty and original behavior of Dianema urostriatum can be observed every day.

Water parameters and tank setup

For Flagtail Catfish, a tank with a minimum volume of 80–100 liters is recommended, although a larger aquarium always translates into more stable conditions and better opportunities for natural group behavior. The ideal water temperature is between 23 and 27°C, with pH in the range 6.0–7.5 and general hardness up to about 12 dGH. These flexible parameters make Dianema urostriatum a suitable inhabitant for many types of community tanks, provided that sudden fluctuations are avoided.

The basic element of the setup should be a soft, fine-grained substrate. Sand or small, rounded gravel works best because the catfish often probes the bottom with its sensitive barbels. Sharp-edged stones or coarse gravel may cause injuries and infections around the mouth. In MB Store you can find various types of substrate designed specifically for bottom-feeding species, which help maintain both aesthetics and good health of the fish.

Decoration should combine functionality and natural aesthetics. Using driftwood, roots, pieces of bogwood and smooth stones allows you to create safe hiding places, shaded corners and visually appealing structures. Flagtail Catfish willingly explores such areas, especially during the evening hours, when it becomes more active. Adding dried leaves, such as Indian almond leaves, can slightly acidify the water and create an ambiance resembling blackwater biotopes, while also providing natural tannins beneficial for fish health.

Plants are highly recommended, both rooted in the substrate and floating on the surface. They provide cover, diffuse light and stabilize water chemistry by absorbing nitrates. Dense plantings at the back and sides of the tank create secluded zones where shy fish can retreat. At the same time open swimming space in the central part should be maintained so that Dianema urostriatum can move freely. Species such as Amazon swords, Cryptocoryne, Anubias and floating Salvinia or Pistia are excellent choices that harmonize with the South American character of the aquarium.

Filtration must ensure efficient mechanical and biological cleaning, but without generating too strong a current. Flagtail Catfish prefers gentle flow similar to that of its natural environment. External filters and high-quality internal filters available in MB Store make it easy to match performance to the size and stocking of the aquarium. It is worth equipping the intake with a pre-filter sponge to protect the barbels from injuries and to prevent smaller fish or fry from being sucked in. Regular maintenance, including water changes of 25–30 percent weekly, is essential to keep the environment stable and safe.

Behavior, social life and tank mates

Dianema urostriatum is a peaceful, non-aggressive species that feels best in a group. Keeping at least 5–6 individuals is recommended, although even a larger shoal will work well in an adequately sized tank. In a properly arranged aquarium, these fish form loose schools, swimming together mainly around the middle and bottom zones, which greatly increases their confidence and reduces stress. A solitary specimen often becomes more timid, hides during the day and may show reduced activity.

Flagtail Catfish is especially interesting because of its dual lifestyle: it searches the bottom for food like typical catfish, but at the same time willingly ventures into the midwater levels. It sometimes rushes to the surface to take a gulp of air, a behavior linked to its ability to use atmospheric oxygen, inherited from ancestors living in oxygen-poor waters. This behavior is normal and should not be mistaken for signs of disease, provided that the fish shows no other symptoms of distress, such as clamped fins or frantic gasping.

When choosing companions for Dianema urostriatum, it is worth focusing on peaceful species with similar environmental requirements. Ideal tank mates include small characins, such as tetras, hatchetfish, rasboras or peaceful dwarf cichlids. Calm livebearers and other non-aggressive catfish species can also be good neighbors. Avoid large, territorial or fin-nipping fish that could harass the Flagtail Catfish or compete excessively for food near the bottom.

Due to its gentle nature and relatively modest size, this catfish is particularly suited to community and biotope aquariums. It does not dig excessively or uproot plants, as some large catfish do, which makes it compatible with carefully arranged planted layouts. Observing how the group patrols the aquarium at dusk, communicates through subtle body movements and reacts to food falling to the bottom, brings a lot of satisfaction and allows you to understand the complex social life of these seemingly inconspicuous fish.

In addition, the presence of catfish in the aquarium has a practical dimension. While Flagtail Catfish should not be considered a simple “cleaning crew”, its natural tendency to search the substrate for leftover food helps maintain order and reduces the risk of organic matter accumulating in hard-to-reach corners. In combination with efficient filtration and regular cleaning equipment offered by MB Store, this contributes to a stable, visually attractive and healthy aquarium environment.

Feeding and nutritional needs

Proper diet is the foundation of long-term health and vitality of Flagtail Catfish. In nature, Dianema urostriatum feeds on small invertebrates, insect larvae, worms and organic debris. In the aquarium it accepts a wide spectrum of foods, but the key is variety and regularity. High-quality sinking granules and tablets for bottom feeders should form the basis of the diet, as they reach the bottom before other fish consume them.

This species eagerly eats frozen and live foods such as bloodworms, tubifex, daphnia and Artemia. These foods not only provide valuable proteins and fats, but also stimulate natural hunting behavior, which has a positive effect on overall condition. It is worth providing such treats several times a week, while monitoring the amount to avoid polluting the water. Overfeeding is one of the most common mistakes; uneaten food quickly decomposes, leading to ammonia and nitrate spikes.

Vegetable components should not be neglected either. Although Flagtail Catfish is primarily carnivorous, supplementing the diet with plant-based granules or small portions of blanched vegetables, such as zucchini or peas, supports digestion and helps maintain a healthy intestinal flora. Products created especially for omnivorous catfish and distributed through specialized stores, including MB Store, provide a balanced composition of animal and plant ingredients tailored to the needs of these species.

Feeding should be done once or twice a day in portions that the fish can consume within a few minutes. It is advisable to feed in the evening or just before the lights go out, as catfish then become more active and have a better chance of reaching the food before faster midwater fish. Observing during feeding whether each individual in the group receives an adequate portion is important; weaker or shyer fish may need an additional feeding spot with food distributed in different areas of the tank.

By ensuring a varied and well-balanced diet, aquarists promote strong immune systems, intense coloration and natural behavior in Dianema urostriatum. Healthy fish are more active, show proper school interactions and are more resistant to common ailments that can result from stress and nutritional deficiencies.

Breeding and sex differences

Breeding Flagtail Catfish in the home aquarium is not yet as common as with many other popular species, but it is certainly possible for meticulous and patient aquarists. The first challenge is distinguishing males from females. Females tend to be slightly larger and more robust, with a fuller belly, especially when filled with eggs. Males are often slimmer and may show a somewhat more intense body shape when viewed from above, though the sexual dimorphism is generally subtle.

In order to stimulate spawning, it is helpful to provide particularly stable conditions, high-quality food and clean water. Some aquarists report success after a partial water change with slightly cooler, soft water, simulating the onset of the rainy season in the natural habitat of these fish. Carefully chosen spawning sites, such as broad leaves, flat stones or quiet corners among roots and decorations, give the pair a safe area to deposit eggs.

Dianema urostriatum shows interesting parental behavior, although it may vary depending on conditions and individual pairs. In some cases, fish guard the spawn for a certain period, driving away other inhabitants of the aquarium. However, to increase the survival rate of eggs and fry, it is often recommended to transfer the eggs to a separate rearing tank equipped with gentle aeration and a sponge filter that will not suck in the tiny fry.

Feeding fry requires careful attention. At first they need very small food, such as infusoria or liquid fry food, and after a few days they can be gradually switched to freshly hatched Artemia and finely crushed dry foods. Maintaining pristine water quality in the rearing aquarium is essential, as young catfish are more sensitive to toxins and rapid changes in parameters than adults. Products, filters and test kits available in MB Store help precisely monitor conditions during this critical phase.

Although breeding Flagtail Catfish can be considered a challenge, it offers a unique opportunity to observe the full life cycle of these fascinating fish. Successful rearing of a healthy generation of juveniles brings enormous satisfaction and deepens understanding of the subtle dependencies between environment, behavior and physiology of Dianema urostriatum.

Creating a dedicated Flagtail Catfish biotope

Many aquarists, after first experiences with keeping Dianema urostriatum in a community tank, decide to create a more specialized setup inspired by its natural environment. Such a biotope not only looks impressive, but also allows the fish to display a wide range of natural behaviors. The starting point is the choice of a suitably spacious aquarium, preferably with a long front pane, which provides more horizontal swimming space and facilitates arranging the bottom area.

To recreate Amazonian conditions, a dark sand substrate works very well, combined with numerous pieces of driftwood and roots creating a complex network of hideaways and passageways. Between them, you can place patches of dried leaves, which gradually decompose, releasing tannins and giving the water a gentle amber hue. This type of arrangement perfectly emphasizes the delicate, subtle coloration of Flagtail Catfish and gives the aquarium a wild, natural character.

Lighting in such a tank does not have to be very strong; moderate or slightly subdued light, combined with floating plants, creates a calm, stress-free environment. Nonetheless, modern LED lamps from the MB Store offer the ability to smoothly adjust intensity and color, enabling the creation of both daytime and evening ambient effects. Gentle shading of certain zones encourages catfish to explore and rest more openly, rather than hiding constantly.

When it comes to plant choice, species originating from South America or visually matching this environment are recommended. Amazons, various Cryptocoryne varieties, ferns attached to roots and epiphytic plants on wood create natural compositions. The open space should be maintained in the front part of the tank, where the catfish most often search the bottom; this also ensures excellent visibility and ease of observation for the owner.

By using properly selected equipment and decorations available in MB Store, from aquariums of different sizes and shapes to effective filtration systems and heaters, aquarists can design a coherent, functional and visually consistent biotope. In such a carefully designed environment, Flagtail Catfish shows its full potential: calm group swimming, social interactions and curiosity typical of a species that has learned to explore complex river systems in the wild.

Essential equipment and how MB Store can help

While Dianema urostriatum is a relatively hardy catfish, its long-term well-being depends on the quality of the equipment used and the consistency of maintenance. A well-chosen aquarium is the foundation. MB Store offers a wide selection of tanks, from compact models for beginners to large, advanced sets for experienced aquarists. Choosing a longer rather than taller aquarium gives Flagtail Catfish more horizontal space for movement and better use of the bottom zone.

The next crucial component is reliable filtration. Filters should provide efficient biological and mechanical filtration while keeping the flow moderate. Many models offered by MB Store allow you to adjust the power and direction of the current, which is especially desirable in aquariums with species from calm waters. Adding a sponge to the intake protects both fish and beneficial bacteria, and at the same time simplifies cleaning and maintenance.

A stable heating system is indispensable for maintaining the optimal temperature range for Flagtail Catfish. Modern heaters with thermostats, available in various power ratings, ensure accurate control of water temperature, reducing the risk of sudden drops or dangerous overheats. For smaller aquariums, one heater is usually sufficient; in larger tanks, two smaller heaters placed at different ends may ensure more even distribution of warmth.

Lighting, though not crucial primarily for the catfish themselves, plays a key role in the overall functioning of the aquarium, especially in planted setups. Efficient LED lamps using energy-saving technology, sold in MB Store, provide sufficient light for plant growth and allow the creation of various visual effects. Adjustable lighting regimes with morning and evening simulations not only improve the comfort of the inhabitants but also enhance your viewing experience.

In addition, MB Store offers a wide selection of accessories that significantly ease daily care: water test kits, nets, siphons, conditioners, specialized food for bottom fish, as well as decorative elements such as rocks, driftwood and ready-made sets of plants. With such comprehensive support, both beginners and advanced aquarists can design and maintain an aquarium in which Flagtail Catfish will live in stable, safe and aesthetically pleasing conditions.

Health, diseases and long-term care

Like most aquarium fish, Dianema urostriatum is susceptible to disease primarily when exposed to stress, poor water quality or improper diet. The first line of defense is always prevention. Regular partial water changes, careful monitoring of ammonia, nitrite and nitrate levels and avoiding overstocking significantly reduce the risk of health problems. Using test kits and conditioners available in MB Store makes it easier to maintain stable, optimal parameters.

Early signs of disease may include lethargy, loss of appetite, clamped fins, unusual spots or lesions on the skin and barbels, or rapid breathing. In the case of Flagtail Catfish, special attention should be paid to the condition of the barbels. Redness, shortening or fraying often indicate sharp substrate, poor hygiene or bacterial infections. Changing the substrate to softer sand and improving water quality frequently leads to marked improvement, especially when combined with appropriately selected treatments.

Common diseases that may affect Dianema urostriatum include parasitic infections, such as ichthyophthiriasis, as well as fungal and bacterial diseases. Before administering any medication, it is advisable to carefully read manufacturer instructions and, if possible, consult experienced aquarists or a veterinarian with expertise in ornamental fish. Some preparations may be more stressful for catfish and other sensitive species, so careful dosing and observation of the aquarium inhabitants during treatment are crucial.

Long-term care also involves ensuring a calm environment and avoiding sudden changes. Moving decorations, disturbing the substrate too aggressively or introducing new tank mates without proper quarantine can cause unnecessary stress. It is better to perform maintenance regularly but moderately, for example weekly, rather than sporadically in a very intensive manner. Consistency is key to maintaining balance in the aquarium ecosystem.

With thoughtful care, quality equipment from MB Store and a bit of patience, Flagtail Catfish can live in the aquarium for many years, delighting with its elegance and calm presence. This species repays good conditions with robust health, natural behavior and an unpretentious charm that often makes it a favorite among all the inhabitants of the tank.

Is Flagtail Catfish a good choice for you?

Deciding to keep Dianema urostriatum depends on a few factors: available tank size, willingness to maintain regular care routines and interest in observing relatively subtle, but very engaging behaviors. For aquarists who value peace, observing social interactions and a naturalistic look of the aquarium, Flagtail Catfish is an excellent candidate. It suits both community and biotope setups and can coexist well with many popular species, provided aggression and excessive competition are avoided.

Beginners who are willing to learn about basic water chemistry, proper feeding and group needs of this catfish can successfully care for it, especially if they start with a well-planned, stable aquarium. More advanced aquarists will appreciate the possibility of breeding attempts, designing themed biotopes and combining Dianema urostriatum with other interesting species from the same region.

By choosing this catfish and using appropriate aquariums, filtration systems and accessories offered by MB Store, you can create a long-lasting, balanced and visually attractive aquatic environment. Flagtail Catfish will become not only a decorative element but also an indicator of good practices in aquaristics: if it is active, curious and healthy, it usually means that the entire tank functions harmoniously. For many aquarists, this is the best proof that careful work, knowledge and passion bring beautiful results.

FAQ about Flagtail Catfish – Dianema urostriatum

How large should the aquarium be for Flagtail Catfish?
For a small group of Flagtail Catfish, an aquarium of at least 80–100 liters is recommended, preferably with a long front pane that provides more swimming space along the bottom. A larger tank offers more stable water parameters, better opportunities for natural group behavior and easier combination with other peaceful species in a community setup.

What water parameters does Dianema urostriatum require?
Flagtail Catfish prefers temperatures between 23 and 27°C, pH 6.0–7.5 and moderate hardness up to around 12 dGH. It is quite adaptable, but poorly tolerates sudden fluctuations and elevated nitrogen compounds. Regular partial water changes and effective filtration are essential to maintain stable conditions similar to its natural Amazonian habitat.

Is Flagtail Catfish suitable for beginners?
Dianema urostriatum can be a good choice for beginners who are ready to learn basic aquarium maintenance and provide appropriate conditions. The species is peaceful and relatively hardy, but requires group keeping, soft substrate and stable parameters. Using reliable equipment and advice from specialized stores, such as MB Store, greatly facilitates successful care.

What should Flagtail Catfish be fed?
Flagtail Catfish should receive sinking granules and tablets for bottom feeders as a dietary base, complemented by frozen or live foods like bloodworms, daphnia and Artemia. Occasional vegetable components, such as plant-based granules or blanched vegetables, support digestion. Feeding once or twice daily in moderate portions helps maintain good health and water quality.

Can Flagtail Catfish be kept with other fish?
Yes, Dianema urostriatum is an excellent inhabitant of peaceful community aquariums. It coexists well with small tetras, rasboras, peaceful dwarf cichlids and other non-aggressive species. It is important to avoid large, predatory or fin-nipping fish that could stress or injure the catfish. Properly selected tank mates help them display natural, calm behavior.