ur first factsheet of 2018 takes us to a family of
catfishes that are loved by most cat enthusiasts,
namely the Doradidae and this month the "Black
Top Mouse Catfish",
Hasser orestis has our focus.
In days gone by this was in most literature, and can
still be found today, under the synonym Hassar notospilus
is similar looking
this species has longer leading fin rays and sports
a clear dorsal with black markings at the base. The
genes Hassar also differs from its close
relative Opsodoras in having an elongate
eye (Opsodoras round eye) and long snout
(snout shorter with a more rounded profile in Opsodoras)
- showing the long snout and the elongate eye
For a large species
it is non aggressive and can be kept with smaller
species such as small characins, dwarf cichlids, small
labyrinth species and also other small catfish such
as Corydoras and the smaller members of the
Loracariids. Provide a soft substrate such as fine
sand as they like to sift through this for edibles
and a sharp substrate could cause damage to its fine
Amazon, Orinoco and Essequibo River basins.
Head narrow with long snout.
Maxillary barbels reaching pectoral, with small barblets.
Mental barbels papillose. Lateral plates small, the
largest approximately 1.33 times the size of the eye.
Large foramen present on occipital
Body light grey, underside
white. Minute black spotting around base of dorsal.
Conspicuous black blotch in dorsal.
Care & Compatibility
This is a particularly delicate
aquarium fish with low tolerence to adverse water
conditions and disease. Lone individuals will not
do well in an aquarium setup so a group of three or
more will be more beneficial to the long term health
of this species. A planted aquarium is a must as they
like to hide in the roots more so than having a rock
or wood setup. Can be kept with smaller species such
as small characins, dwarf cichlids, small labyrinth
species and also other small catfish such as Corydoras
and the smaller members of the Loracariids.
Males possess an elongated
first dorsal ray. Females have more rounded pectoral
fins than males.
Tablet foods, small live and
frozen foods such as worms and Daphnia.
Maxillary barbels:Pertaining to the upper jaw. (maxillary barbels). Mental barbels: Pertaining to the
chin, on the lower jaw. (mental barbels).
Papillose:A small fleshy
projection, plural papillae. Lateral: A sensory line, along the
sides of the body. Foramen: magnum (Latin: great hole)
is a large oval opening (foramen) in the occipital
bone of the skull in humans and various other animals.
It is one of the several oval or circular openings
(foramina) in the base of the skull. Occipitalprocess:
A median bone on the upper surface of the back of
the head; pertaining to the occiput. Dorsal: The primary rayed fin(s)
on top of the body.
Hassar: From the Aruac name of the fish. orestis: A mountaineer.
H.A. and R. Riehl 1985
Aquarien atlas. Band 2. Mergus, Verlag für Natur-
und Heimtierkunde GmbH, Melle, Germany. 1216 p. Catfish Association of Great Britain:
Information Book 6, 1980. 18p.