thought to myself, lets have something really weird
for the August 2018 factsheet and here it is the only
member of the Nematogenyidae family and a Chilean
catfish to boot the "Mountain Catfish" Nematogenys
this single species, N. inermis. The genus
is endemic to some rivers in Chile. The common name
for this species is "Mountain Catfish".
Previously in the Trichomycteridae family and is very
rare in the aquatic hobby. There was a fossil which
was found and described from the Miocene, continental
fluviolacustrine deposits of the upper Cura–Mallín
Formation (37–39°S), Chile (Azpelicueta
& Rubilar, 1997). That species was named as Nematogenys
has no adipose fin and and the caudal fin is short
inermis- Line drawing by W. S. Atkinson from Eigenmann
1927: Pl VII
This species is
considered very primitive, mainly because it has three
pairs of barbels, opercula and subopérculos
without thorns, thorns of the pectoral fin and dorsal
fin a level of the pelvics. However, studies have
shown the reduction of the jaws that they support
the chins and specialication in the loss of bones
like the opisthotic, subopercular, interopercular.
inermis, is a species whose distribution and
abundance is in frank decrease. The main reasons for
its reduction are the direct alteration of its habitat
by decrease of flows, dredging, channeling, fragmentation,
alteration of regimes of flow, sedimentation, deforestation
of the riparian zone and pollution. It is also very
vulnerable to predation by introduced species.
In its native
Chile its common name is "Catfish" or "Big
localities in Concepción, Rancagua and Angol,
Chile. Formerly widespread throughout much of Central
Chile. Type locality: Chile.
Flattened head dorsoventrally.
Dorsally, a longitudinal groove is seen between both
halves of the epiaxial musculature and the body thins
notoriously towards the caudal region. They present
a wide mouth with small teeth in large quantity. They
have three pairs of barbels; maxilla, nasal and mental.
The eyes are small in size and separated by ample
space interorbital. They have only one dorsal fin,
with a narrow base and inserted over the pelvics.
The anal fin is distant from the anus and separated
from the pelvics. The tail fin is large and rounded.
This species also has a large caudal peduncle compressed,
tall and thickened dorsal rim (Ruiz, 1993).
The colouration exhibited
by this fish is yellowish to light brown in the
body, with a large amount of irregular spots, especially
on the fins, the belly becomes clearer on the back
Care & Compatibility
There is not much information
on keeping this species in the aquarium but as it
was a former member of the Trichomycteridae family
then the husbandry pertaining to this would adhere
but studies indicate that in captivity they do not
accept any kind of food, dying after months.
An aspect of its reproduction
indicates that it belongs to the category of partial
synchronism, it is to say, will spawn once a season.
The spawning period would occur in late spring or at
the beginning of summer (Manríquez et al ., 1984).
The feeding items for this
species are basically benthic. Studies indicate that
in captivity does not accept any kind of food, dying
after months (Manríquez et al ., 1982). According
to Oliver (1949), these fish feed at night, worms
and insects. The examined stomach content reveals
that the most frequent item is Hemiptera, followed
in importance by Amphipoda and Diptera (chironomidae).
fin: The median, unpaired, ventrally located
fin that lies behind the anus, usually on the posterior
half of the fish.
Adipose fin: Fleshy finlike projection without
rays, behind the rayed dorsal fin.
Caudal fin: The tail. Caudal
peduncle: The narrow part of a fish's body
to which the caudal or tail fin is attached.
Dorsal fin: The primary rayed fin(s) on top
of the body. Interoperculum:
Between the preoperculum and the operculum, sometimes
very small, and in some Loricariidae bearing
spines. Maxillary:Pertaining to the upper jaw. (maxillary barbels). Mental: Pertaining to the chin, on
the lower jaw. (mental barbels). Nasal: On top of the head, by the nostrils.
(nasal barbels). Opisthure: The tip of the vertebral
column which protrudes beyond the caudal fin.
Pelvic fins: The paired fins, between the pectorals
and the anal fins. (also referred to as ventrals). Subocular:
Beneath the eye.
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.
de Pínna, M.C.C., 2003. Nematogenyidae
(mountain catfishes). p. 268-269. In R.E. Reis, S.O.
Kullander and C.J. Ferraris, Jr. (eds.) Checklist of
the Freshwater Fishes of South and Central America.
Porto Alegre: EDIPUCRS, Brasil. 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. 2017.
FishBase. World Wide Web electronic publication. www.fishbase.org,
( 02/2017 ).