Max Size: 13cm

Flagtail Catfish (Dianema urostriatum)

Flagtail Catfish are a very peaceful fish that is suitable for many community aquariums. These fish will not harm even the smallest tankmates, although tiny babies may be accidentally sucked up. Their peaceful demeanour and ease of care make them excellent fish for the beginner aquarist.

Although you can keep the Flagtail Catfish on its own, you will find that these fish are far more outgoing and active if you maintain them in a group of 5 or more individuals. Strangely for Catfish, you will occasionally see them swimming in a shoal in midwater when kept in this way.

Ideal tankmates could include medium to large-sized Tetras, Rainbowfish, medium-sized Rasboras, peaceful Cichlids, Corydoras Catfish and Loaches. However, it would be best to avoid much larger or aggressive species, although these fish are pretty robust.

The ideal aquarium setup for these fish would be a biotope aquarium consisting of sandy substrate and tangles of driftwood and roots. You can further mimic their natural habitat by adding a few handfuls of dried leaves such as oak or beech and scattering them around the bottom of the aquarium. However, Flagtail Catfish are unfussy and can be just as happy in any setup as long as it is heavily panted with plenty of cover.

Flagtail Catfish have a greyish brown body and head. The upper half of their body is covered in small black spots, and the lower half of their body is a silvery colour. The distinguishing characteristic of this species of Catfish is their caudal fin; it is strikingly marked with horizontal black and white alternating stripes. In addition, these fish have a pair of barbels on each side of their snout.

Quick Facts
Scientific NameDianema urostriatum
Other NamesFlagtail Porthole Catfish, Stripedtail Catfish
Aquarium LevelBottom
DifficultyBeginner - Intermediate
Best kept asGroups 5+
ReproductionBubble nest
Lifespanup to 10 years
Water Parameters
Water TypeFreshwater
PH6.0 - 8.0
GH5 - 20
72 - 82℉
22.2 - 27.8℃

Photos of the Flagtail Catfish

Flagtail Catfish

Natural Habitat

The Flagtail Catfish is endemic to the Amazon River Basins in Brazil in South America. They can be found in shallow, slow-moving tributaries and backwaters, as well as lakes, creeks and ponds. Their habitat contains a sandy substrate with some aquatic vegetation.

What to feed the Flagtail Catfish

Flagtail Catfish are easy to feed because they will eat a wide variety of foods. They are also enthusiastic feeders who will quickly adjust to their aquarium surroundings and take food at the water's surface and substrate.

It would be best to feed them a varied diet mainly consisting of meaty foods such as bloodworms, chopped earthworms and brine shrimp, supplementing that with good quality dried food such as flake or pellets alongside frozen or freeze-dried foods. It would also be beneficial for your fish if you occasionally provided them with some vegetable matter in the form of blanched courgette, spinach and cucumber.

It is best to feed them a few times per day, however only provide what they will consume within a few minutes.

How to sex the Flagtail Catfish

It is somewhat straightforward to differentiate between the male and female Flagtail Catfish. Adult males possess thickened traversing pectoral fin rays. In contrast, mature females are rounder and fuller-bodied than males.

How to breed the Flagtail Catfish

Minimal information exists regarding the spawning of these fish in captivity; however, it has been achieved numerous times. It's supposedly a bubble nesting species, although some conflicting information suggests they lay their eggs in pits dug in the substrate.

If you would like to try and breed the Flagtail Catfish, it would probably be better to start with a small group of 4 to 6 individuals. Then, add a piece of polystyrene or a plastic lid of some kind to float at the surface and provide a potential site for nest-building. Ideally, you should also secure the object in one place. Extensive amounts of live food are essential to bringing the fish into condition, as are significant, cool water changes.

As soon as you notice any eggs, you should remove the adults straight away as they will eat them if given a chance. Once the fry has consumed their yolk sacs, they should be big enough to take microworm and baby brine shrimp.

If you are having trouble inducing a spawn, you could attempt a full-on simulation of the dry and wet seasons that transpire in their natural waters. The fish spawn at the start of the wet season, so first, lower the water level in the tank, then increase the temperature by a few degrees and do not feed the fish for a few weeks to mimic the dry season. You could also remove the filter and slightly increase the water's hardness. An increase in both dissolved salts and organic compounds are associated with the dry season only because there is scarcer water around to dissolve them.

After a few weeks, you should then increase the water level using cooler water and begin feeding the fish profoundly. Then, replace the filter if you removed it, and if the hardness of the water was increased, use very soft water for topping up.

If your fish are still unwilling to spawn, remember that features such as the time of year and barometric pressure can also affect breeding activity in many South American species. The wet season happens roughly between September and April, depending on geography, so it may be that some species will only spawn throughout these months.

Other Catfish of interest

African Glass Catfish(Pareutropius debauwi)
Common Otocinclus(Otocinclus vittatus)
Cuckoo Catfish(Synodontis multipunctatus)
Glass Catfish(Kryptopterus vitreolus)
Marble Sturisoma Whiptail Catfish(Sturisoma aureum)
Spotted Hoplo Catfish(Megalechis thoracata)
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Date Added: 28/10/2021 13:15:44 - Updated: 22/11/2021 16:02:21