his month (April 2015) we are concentrating on a little known
family, in the aquarium trade anyway, and that is the Cetopsidae.
When you think of this family you think right away of the candiru
and other parasite catfish which can be nasty but H. marmorates
is very different to this behaviour and is recomended in groups
in an aquarium.
A little bit of history
on this species and three others in the Helogenes
genera, H. castaneus (from the Rio Meta basin,
Colombia) H. gouldingi, (from the Rio Madeira
basin, Brazil) and H. uruyensis from southern
Venezuela. They were all in the previously named Helogenidae
family but were incorporated into the Cetopsidae family
in 1995 and consequently in the sub-family Helogeninae.
H. marmoratus although scarce in the hobby seems
to be the only one out of the four species that is sometimes
exported from the trade.
When Günther described H.
marmoratus in 1863 he placed it in the Hypophthalmidae
and it was not until 45 years later that Eigenmann on
its second collection that he removed Helegenes from
Hypophthalmidae and described a new family for it, the
Helogeneidae. The species remained monotypic for a further
nearly 80 years until Delsman described a second species,
H. amazonae based on a single species caught
in the vicinity of Manaus, Brazil, this turned out later
to be a synonym of H. marmoratus. Another species
was named by Dahl in 1960 and naming it Leyvaichthys
castaneus. This later was renamed Helegens castaneus
and the main discription was the lack of an adipose fin,
hence the new genus name. This variability within the
Helogenidae concerning the adipose fin which ranged from
the Peruvian populations from relatively small, through
very small, to being totally absent and this absence of
the fin had been used to distinguish, wholly or in part,
the genus Leyvaichthys from Helegenes.
The possession of nine principal fin rays in the lower
lobe of the caudal fin of Helogenes marmoratus
distinguishes it from H. gouldingi and H.
castaneus, which have eight principal rays on the
lower lobe of that fin. The 39-48 anal-fin rays of H.
marmoratus separates that species from H. uruyensis,
which has 32-37 anal-fin rays.
is a typical inhabitant of black or clear waters, and
is usually found in forest streams with a moderate to
swift current flow over firm sand or gravel bottoms. Lives
hidden under plants, litter or plant debris. Can easily
be mistaken as a piece of dead wood when it rests on its
side, and lies motionless on the bottom. Often swims on
one side in undulating movements.
This is a catfish that likes the
upper levels of the aquarium. It likes to hide in plants/vegetation
at the surface so either floating plants or long strands
of Valisineria plants would work better as they will be
unhappy in a bare unplanted tank. This trait can be seen
in the upper image.
fin rays in the lower lobe of the caudal fin. 39-48 anal-fin
rays. Dorsal fin small and set well back, anal fin long. Adipose
fin is is very small sometimes lacking, dorsal and pectoral
fins without spines. Eyes are small, directed upward and outward.
The maxillary barbels fit into a groove below the eye.
Head and body reddish brown with a marbled
pattern which is variable. Dorsal, pectorals, ventrals, anal and
adipose fins are the same colour as the body but all have lighter
margins. Caudal fin light brown with darker mottling.
Can be kept with a vast variety of peaceful
fish as long as they are not too small, but would be better to
keep at least six specimens of this small species in a tank of
|A nocturnal species
that needs plant cover to rest in during daylight hours.
Does not like too much of a water
movement in the aquarium.
| Not recorded.
In its natural habitat it feeds mainly on
terrestrial insects, particularly ants. In the aquarium it will
eat most aquarium prepared foods, small live foods, insect larvae
and small worms. Feed prior to turning of the tank lights if housed
with other species.
Helos = marsh; genus = born.
marmoratus: Marbled; mottled.
Top: © Yann
The primary rayed fin(s) on top of the body
Caudal fin: The
Anal fin: The
median, unpaired, ventrally located fin that lies behind
the anus, usually on the posterior half of the fish.
Pectoral fin: The paired fins just behind the
The paired fins, between the pectorals
and the anal fins.
Fleshy finlike projection without
rays, behind the rayed dorsal fin.
Maxillary barbels: Pertaining to the
upper jaw. (maxillary barbels)
and R. Riehl 1991
Aquarien atlas. Bd. 3. Melle: Mergus, Verlag für Natur-
und Heimtierkunde, Germany. 1104 p.
Froese, R. and D. Pauly. Editors. 2014.FishBase.
World Wide Web electronic publication. www.fishbase.org,
Ferraris, C.J. Jr., 2007. Checklist of
catfishes, recent and fossil (Osteichthyes: Siluriformes),
and catalogue of siluriform primary types. Zootaxa 1418:1-628.
Vari, R.P. and H. Ortega, 1986. The catfishes
of the neotropical Family Helogenidae (Ostariophysi: Siluroidei).
Smith. Contrib. Zool. (442):20 p.
Le Bail, P.-Y., P. Keith and P. Planquette,
2000. Atlas des poissons d'eau douce de Guyane. Tome 2,
Fascicule II: Siluriformes. Collection Patrimoines Naturels
43(II): 307p. Paris: Publications scientifiques du Muséum
national d'Histoire naturelle.
Bott: © Billy Grant
America: Atlantic drainages
of Guianas, upper Orinoco and Negro systems and upper Amazon
River basin. Madre de Dios region, Peru.
Type locality: Essequibo
| 7.5cm. (3ins)
|If you found this page
helpful you can help keep ScotCat running by making a small