Fish, Tanks and Ponds

Fish, Tanks and Ponds
A comprehensive guide to fish

Dianema urostriatum

Flagtail catfish

Flagtail catfish, Dianema urostriatumFlagtail catfish, Dianema urostriatum
Photos by Andy Rapson


Dianema: Greek, di = two + Greek, nema = filament

General Notes:

When kept in an established group this catfish can often be seen swimming in a shoal in mid water. They are very peaceful and they look great in a group when housed with other peaceful fishes.
They appreciate plenty of cover in their tank and they need to have some open swimming spaces. They don't harm plants and they would thrive in small community in a planted aquarium. As with Corydoras their barbels could be damaged if kept over a sharp substrate so using sand is highly recommended. Once established Dianema urostriatum is a hardy fish which should live for many years.


Use live or frozen daphnia, cyclops, blood worms, glass worms and similar for the main part of the diet and supplement this with a good quality flake food or suitably sized pellets in order to ensure a balanced diet. 


Dianema urostriatum are reliably peaceful even with very small fish. They can be kept in groups with their own kind without any problems, in fact they do better when kept in a group as single specimens tend to be a little shy. 


When adult the females are heavier in the body than are the males. 


Dianema urostriatum  has been bred by hobbyists but there is no verified account of this. Breeding this fish is still regarded as a serious challenge.
Eggs are attached to floating cover after the fish has been exposed to conditions which simulate the wet and dry season in its natural environment and then conditioned by using lots of high protein live or frozen food.

Wild status

Wild populations of Dianema urostriatum have not  been evaluated.

Additional information

Dianema urostriatum is a little delicate until it has been acclimatised to your aquarium. If losses are going to occur it is normally soon after the fish has been introduced to the new tank. Keeping the water soft and mildly acidic seems to help to reduce any potential losses.

Information at a glance

pH: 6 - 8
dGH: 5 - 15
Temperature: 25 - 28°C (77 - 82°F)
Diet: Omnivore
Size: 12.5cm (5in)
Min tank size: 100 litres
Difficulty level: Easy
Aquarium type: Community
Swimming level: Lower

Distribution and habitat

distribution map for Flagtail catfish, Dianema urostriatum

Origin: South America: Amazon River basin.

Habitat: Rivers, creeks and pools


Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Siluriformes
Family: Callichthyidae
Genus: Dianema
Species: D. urostriatum (Miranda Ribeiro, 1912)

Other common names:
Striped-tailed Catfish, Dianema, Rondon

Synonyms: Decapogon urostriatum