Flagtail catfish (Dianema urostriatum) care guide

Group
Freshwater fish
Other names
Flagtail porthole catfish, Flagtail hoplo, Stripe-tailed catfish
Family
Callichthyidae (armoured catfishes)
Origin
South America: the Amazon basin in Brazil; described from near Manaus, Amazonas.
Water
freshwater
Maximum size
8.4 cm
Temperature
25–28°C
pH
6–8
Hardness
Soft water preferred for acclimatisation
Minimum tank
120 litres
Care level
intermediate
Temperament
peaceful

Care

The flagtail catfish is a slender armoured catfish related to the hoplos and corys. Unlike corys it spends much of its time hovering in midwater, often resting on plant leaves, which makes it a good larger catfish for a community tank. It is sociable, so keep a group of at least five or six. The 120-litre minimum given here is our estimate for a small group of adults. Provide caves (rock or pipe), driftwood and plenty of plants, with some broad leaves and floating cover that the fish can rest on, and a soft sand base. PlanetCatfish gives 25–28 °C and pH 6.0–8.0, but notes that newly imported fish can be fussy and should be settled in slightly soft water at around pH 6.0–6.5. Keep the water clean and well oxygenated. Identification: the tail fin has bold black and white horizontal stripes. The only other species in the genus, Dianema longibarbis (the porthole catfish), has a plain, clear tail. Sexing: females are heavier-bodied than males. It is listed as Least Concern on the IUCN Red List (PlanetCatfish, assessed 2018). Sources: PlanetCatfish (planetcatfish.com/common/species.php?speciesid=124). Checked October 2026.

Diet

Accepts a wide range of prepared foods, including flake, sinking pellets and frozen foods, for everyday feeding. Live foods are recommended when conditioning for breeding.

Breeding

Possible but not common. PlanetCatfish says the fish should be fed plenty of live food and taken through a simulated dry season followed by a wet season (for example, softer, cooler water changes and a rise in water level) to trigger spawning. The eggs are attached under floating cover in a circular cluster, similar to cory eggs. Females are heavier-bodied than males.

Compatibility and tank mates

A very docile midwater catfish, ideal with peaceful community fish such as tetras, pencilfish, hatchetfish, dwarf cichlids, corys and small plecos. Avoid fin-nippers and large aggressive fish.

Last updated 5 October 2026. Community-edited care guide on Aquatic-Auctions.

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