here are only two species in the genus Dianema,
the other being longibarbis, the Porthole cat. This is
of course the Flagtail cat as looking at the image you can see
this trait in the caudal fin, it shares these unusual markings
along with Corydoras robineae, it is also placed in the
same family, Callichthyidae.
In body shape it looks like an elongated
Corydoras with quite large eyes placed laterally, and possessing
four pairs of barbels and a deeply forked caudal fin.
To tell the males from females is not easy but the hard rays in
the males pectoral fins tend to be a little thicker than the females.
As a show fish they tend to fold their caudal fin when placed
in a show tank and they never seem too happy in the confined
On my collecting trip to Iquitos, Peru in 2000 I collected the
other Dianema (longibarbis) so these only two species
from the same genus are very many miles apart and so I find it
strange that they are so alike, apart from the caudal fin, where
longibarbis has no markings at all.
Head depressed, width much less than the
depth of the body. The fontanel is elongate and the supraoccipital
does not form a backward projection. The suborbital is very narrow
and naked and the nuchal plates fuse along the midline between the
supraoccipital and the dorsal. The abdomen between the pectoral
fin bases is usually completely covered by the expansion of the
coracoids. There is no azygous predorsal plate. The eyes are large
and lateral in position. The lower lip has two to four pairs of
short barbel-like flaps in addition to the rictal barbels; the rictal
barbels extend to the pectoral fin origin or beyond. The dorsal
fin has a spine and 7 or 8 soft rays, its base length contained
1 to 1½ times in its distance from the adipose fin. The caudal
fin is forked.
Ground colour of head and body grey/brown,
upper half of body covered with small black spots, which can vary
in number. Lower half of body silvery grey. Caudal fin is strikingly
marked with black and white stripes. Remaining fins pale tan.
This is a peaceful midwater to bottom swimmer
that will do better if kept in a group of at least 4 as individuals
on their own tend to sulk and never seem to progress too well. Try
to resist placing them in an aquarium with aggressive species such
as some Cichlids, they will do better with the usual community type
fish and of course along with Corydoras sp.
This fish has proved a challenge for quite
a few catfish enthusiasts, including myself, over the years. There
has been unconfirmed reports of breeding triumphs but no documentation
as yet to prove this theory. It is reported to be a bubblenest breeder
just like its cousins in the Hoplo/Megalechis/Lepthoplosternum-complex.
Omnivorous, taking most foods but preferring
live and frozen such as daphnia, worms, white and grindal, and bloodworms.
Will also accept good quality flake and tablet foods.
Riehl, R. and H.A. Baensch
1987 Aquarien Atlas. Band. 1. Melle: Mergus, Verlag für Natur-
und Heimtierkunde, Germany. 992 p.
Dia = through;
nema = thread. The gender of this name is neuter,
not feminine as usually thought.
Burgess, W.E. 1989 An atlas of freshwater and marine
catfishes. A preliminary survey of the Siluriformes. T.F.H. Publications,
Inc., Neptune City, New Jersey (USA). 784 p.
Left picture: Helen Burns
Right picture: © Danny
Blundell @ The Danny Blundell Photo Gallery