n to the month of August 2005
we welcome back author Chris Ralph who is the catfish
expert to the U.K. fishkeeping magazine 'Tropical
Fish'. Chris concentrates on his favourite cats 'The
biggies' with a look at the Asian catfish, Ompok
particular species can be found widespread throughout
Asia in the rivers of Afghanistan to China, Thailand
and Borneo. This particular catfish has endangered
status in the Western Ghats in India and is documented
as being found in both freshwater and brackish environments.
Ompok bimaculatus naturally occurs in streams
and rivers which range in size and flow with currents
that can best be described as sluggish to moderate.
The rivers are usually quite shallow ranging from
0.5 to 1.5m in depth, and are often muddy and murky.
These large catfish are also found in canals and inundated
fields into which they move during the flood season.
These catfish can attain a length of 450mm or 18”
The ideal water
parameters for these catfish are pH in the range of
6-8, hardness in the range of 4-28°dGH and temperature
in the range of 20-26°C. This is one of the larger
species of catfish, and due to the size that it can
attain I would not recommend that you keep this catfish
in with small fish as they are most likely going to
form part of its diet. Also this particular species
requires a larger size aquarium and I would suggest
a minimum of 72” x 24” x 24” for
it. You are most unlikely to see this catfish amongst
importations due to the fact that it is a food fish
in the countries in which it naturally occurs. Where
offered for sale as a food fish you might encounter
Ompok bimaculatus being sold fresh or smoked
- head view
siluriodes was at one
time a synomyn for O. bimaculatus but O.
siluriodes has a marbled body pattern against
the silver of O. bimaculatus.
450mm s.l. (standard length
is the measurement from the tip of the snout to the
base of the caudal peduncle).
is elongated? The dorsal fin is described as being
small and has a total of 4 soft rays, whilst the anal
fin which is described as being long has a total of
54-74 soft rays. The pelvic fins are described as
being small with 7-8 soft rays. The pectoral fins
have 12-14 soft rays. The caudal fin is forked. Ompok
bimaculatus has two pairs of barbels; one pair
of maxillary barbels which reach the reaching anal
fin; and one pair of mandibular barbels which are
described as being small in length. The eyes are small
and are covered by skin. Ompok bimaculatus
is described as having vomerine teeth in 2 patches.
The base colour of the body
is silver, with a conspicuous round black blotch
above and behind the pectoral fin base. The second
of the two spots is at the base of the caudal peduncle
hence the species name bimaculatus.
Care & Compatibility
bimaculatus is described
as being peaceful but, has quite a large mouth, and
it is for this reason that I would suggest that you
keep this catfish as part of a shoal of its own kind
or with other large species of fish.
There are no known documented
spawnings of this catfish in aquaria, which is most
likely due to the fact that this catfish is rarely imported
and also due to the size of aquarium required. Whilst
there are no documented aquarium spawnings it is documented
that these catfish are bred in India using hormone injections.
The males tend to be more slender
than the females and are described as having serrations
on the posterior edge of the pectoral fin spines, whilst
the female’s pectoral fins lack these serrations.
The natural diet of this catfish
includes vegetable matter, fish, crustaceans and molluscs.
In captivity these catfish readily accept catfish
pellets, prawns and frozen foods.
- in relation to the mandible or lower jaw.
Maxillary - in relation to the maxilla, the
bone of the upper jaw. Vomerine - teeth present on the vomer.
Vomer - the anterior bone in the mid-line
of the roof of the mouth.
It has been suggested that the name is a bad reproduction
of the Malay name 'limpok'. Or from the vernucular
name, 'Ompok'. bimaculatus: With
R. and D. Pauly.
Editors. 2005. FishBase.World Wide Web electronic publication.
www.fishbase.org, version (07/2005).