Armored Catfish (Callichthyidae)

Flagtail Catfish

Dianema urostriatum

Dianema urostriatum, more commonly known as the Striped-tailed Dianema or Flagtail Catfish, belongs to the family Callichthyidae (Armored or Callichthyid Catfishes). Its origin is associated with the vast Amazon River basin in South America, where the main population inhabits the middle reaches, amidst tropical forests. This fish can be found ubiquitously in small streams and rivers, where it occupies both the water column and the bottom layer.

Tank
from 140 L (37 gal)
Temperature
25 – 28 °C (77 – 82 °F)
Size in aquarium
10 cm (3.9 in)
Acidity
pH 6–8
Natural rangeRange on the map
  • Rio Negro area
  • South America area
  • Brazil

Tank conditions

Plan the tank stocking
Temperature
25 – 28 °C (77 – 82 °F)
Water pH
Slightly acidic (6) – Slightly alkaline (8)
Water dH
Soft (5) – Very hard (19)
Water salinity
no salt (freshwater)
Size in aquarium
10 cm (3.9 in)
Lifespan
8 years
Temperament
Peaceful, active/mobile
Toward small fish
not a predator
Required aquarium volume
from 140 L (37 gal)
Lighting
dimmed or moderate
Substrate
any, but dark
Water flow
weak or moderate
Swimming level
near the bottom
Feeding
Any (universal)
Keeping
Small group 3–4 individuals
Jumping
noticeable a lid is needed
  • Lifespan. A lifespan to expect under good care, not a measured value: it depends heavily on tank volume, water quality and diet — and for selectively bred forms, on their origin as well.
  • Toward small fish. Based on the Predators category in the catalog or the temperament in the species parameters. “A risk to small fish” means the species is not a predator by habit, yet will swallow any fish that fits in its mouth.
  • Required aquarium volume. This is a husbandry recommendation, not a measured value: the volume depends on the keeping mode (small group (3–4 individuals)), footprint, decor and tank mates.

Care and keeping

Description

Adult specimens of this fish reach a length of about 10 cm. Its appearance differs slightly from typical catfishes, which are usually characterized by a somewhat flattened body and a massive head with a wide mouth. The morphological features of the Flagtail Catfish are explained by its lifestyle: it spends significant time swimming rather than on the bottom, which has left its mark. Therefore, its body is robust, fins are well-developed, and the head has a pointed shape. One of the most recognizable features of the species is its tail, adorned with a striped pattern of alternating black and white horizontal bands. The body coloration of the fish is gray with dark speckles.

Habitat

The species inhabits South America, predominantly in the Amazon River basin and its tributary, the Rio Negro. In nature, it occupies slow-flowing tributaries and streams with shaded areas, where the bottom is covered with soft sand or silt. The biotope is characterized by dense riparian and floating vegetation, creating diffused lighting.

Behavior and Compatibility

This fish is distinguished by its mobility and friendly disposition. It prefers to be in a group, optimally 3–4 individuals. Towards other aquarium inhabitants, the Flagtail Catfish is peaceful. It can certainly be kept together with many non-aggressive and non-territorial fish species. For example, good compatibility is observed with related Corydoras, but it should be noted that they do not get along well with some cichlids, such as Geophagus.

Care and Maintenance

For these swimming fish, the optimal aquarium volume starts from 140 L, which corresponds to a side length of 80 cm. When setting up the tank, it is important to provide both open areas for swimming and secluded spots for hiding. Dense plant thickets, snags, pieces of bark, coconut shells, and large leaves of some trees are suitable for this purpose. Dim lighting is recommended; this can be achieved with floating plants that will create natural shading. Successful and long-term keeping of these fish depends on maintaining stable water parameters within the permissible values of key hydrochemical indicators (pH and dGH). Regular aquarium maintenance, including partial water changes and removal of organic debris, will help prevent the accumulation of harmful waste products.

Diet

Usually, acclimatized individuals, as well as those bred and raised in aquarium conditions, easily adapt to offered dry food. Nevertheless, for their health, it will be very beneficial to supplement their diet with live or frozen foods, such as brine shrimp, daphnia, or bloodworms.

Breeding and Reproduction

Spawning is paired and stimulated by imitating the rainy season through frequent water changes and a temperature drop of 2–4 °C. The male builds a bubble nest under broad plant leaves or artificial substrates. After laying up to 500 eggs, the male guards the clutch. The incubation period lasts up to 5 days. Fry are extremely sensitive to water quality and the presence of protein contamination in the first days of life.

Diseases

Fish are susceptible to diseases typical for armored catfishes when keeping conditions are violated. High sensitivity to water quality and organic accumulation can lead to fin and skin damage by bacterial infections or mold fungi. Prevention requires regular filtration, aeration, and weekly water changes, as well as the use of soft substrate to prevent damage to their delicate barbels.

How to choose

When purchasing, one should choose active individuals with clean scales and undamaged fins. It is important to check the integrity of the barbels, as their absence indicates improper keeping conditions in the store. A healthy fish should show interest in food and have no signs of emaciation or whitish film on its body. It is recommended to acquire a group of 3–5 individuals to ensure natural social behavior.

Compatibility

There are no pair reviews for this species yet — check tankmates in the matcher.

All tankmates

Plants and this fish

Matching water does not mean the plant will stay intact.

Frequently asked questions

The essentials: size, tank volume, water parameters and care

How big does Flagtail Catfish get?

An adult reaches 10 cm in length. Plan the tank around the maximum size: the fish quickly outgrows a cramped setup.

What size aquarium does Flagtail Catfish need?

The recommended volume is 140 L. A smaller tank speeds up nitrate build-up and raises stress levels.

What water parameters does Flagtail Catfish need?

Temperature 25–28 °C, pH 6–8, hardness 5–19 dGH. Stability matters more than exact values: sudden swings are harder on the fish than a small deviation from the ideal.

How long does Flagtail Catfish live?

Around 8 years when kept properly. Lifespan depends directly on tank volume, water quality and a varied diet.

Is Flagtail Catfish aggressive?

Temperament: peaceful, active/mobile. Keep this in mind when choosing tank mates.

How many Flagtail Catfish should be kept together?

Recommended setup: small group (3–4 individuals). Ignoring this is a common cause of stress and disease.

What does Flagtail Catfish eat?

Diet type: any (universal). Feed small portions that are finished within a couple of minutes — overfeeding does more harm than underfeeding.

What is the scientific name of Flagtail Catfish?

The scientific name of the species is Dianema urostriatum, family Armored Catfish (Callichthyidae). It also appears in the literature as: Decapogon urostriatum.

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Other scientific names and conservation status

Other scientific names
Decapogon urostriatum
Categories
Catfish
Conservation status
Least concernLC