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
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.
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.
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
drainages of Guianas, upper Orinoco and Negro systems
and upper Amazon River basin. Madre de Dios region,
locality: Essequibo River, Guiana.
22-26°c (71-79°f )
principal 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
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.
Care & Compatibility
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. 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 their
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.
Fleshy finlike projection without
rays, behind the rayed dorsal fin. Anal fin:The median,
unpaired, ventrally located fin that lies behind the
anus, usually on the posterior half of the fish.
The primary rayed fin(s) on top of the body. Caudal fin: The tail. Maxillary barbels: Pertaining to
the upper jaw. (maxillary barbels) Pectoral fin:The
paired fins just behind the head. Ventral Fin: The
paired fins, between the pectorals and the anal fins.
Helogenes:Helos = marsh; genus = born. marmoratus: Marbled; mottled.
H.A. and R. Riehl
1991 Aquarien atlas. Bd. 3. Melle: Mergus, Verlag für
Natur- und Heimtierkunde, Germany. 1104 p. Ferraris, C.J. Jr., 2007. Checklist
of catfishes, recent and fossil (Osteichthyes: Siluriformes),
and catalogue of siluriform primary types. Zootaxa 1418:1-628.
Froese, R. and D. Pauly. Editors. 2014.
FishBase. World Wide Web electronic publication. www.fishbase.org,
( 11/2014 ). 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. Vari, R.P. and H. Ortega, 1986. The
catfishes of the neotropical Family Helogenidae (Ostariophysi:
Siluroidei). Smith. Contrib. Zool. (442):20 p.