Ompok bimaculatus (Bloch,
1794)
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On 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 bimaculatus.
his 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” standard length.
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 on skewers!
Above picture depicts a xanthic variety
of this species. It is not an albino version as it does not sport
red or pink eyes.
The body 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 brown, which
is usually marmorated or blotchy 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.
Ompok 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.
| Sexual
differences |
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.
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| Breeding |
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 natural diet of this catfish includes
vegetable matter, fish, crustaceans and molluscs. In captivity these
catfish readily accept catfish pellets, prawns and frozen foods.
| Etymology |
Ompok:
It has been suggested that the name is a bad reproduction
of the Malay name 'limpok'. Or from the vernucular
name, 'Ompok'
bimaculatus : With two spots
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| Glossary
of Terms |
Mandibular
- 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.
Xanthic (zan'thik) - of a yellowish colour.
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| References |
Froese, R. and D. Pauly.
Editors. 2005. FishBase.World Wide Web electronic publication. www.fishbase.org,
version (07/2005).
www.planetcatfish.com
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| Synonyms:
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| Silurus bimaculatus,
Callichrous bimaculatus, Pseudosilurus bimaculatus, Phalacronotus
siluroides, Ompok siluroides, Ompok canio, Silurus canio, Schilbe
pabo, Silurus chechra, Silurus duda, Callichrus affinis, Callichrus
immaculatus, Callichrus nebulosus, Wallago microcephalus, Silurus
mysoricus, Silurus indicus, Callichrous gangeticus, Callichrous
macrophthalmus, Callichrous sindensis, Wallago miostoma, Ompok
sindensis. |
| Common
Name: |
| Two-spot
Glass Catfish, Glass Catfish, Butter Catfish |
| Family: |
| Siluridae or Sheathfishes |
| Subfamily: |
| Silurinae |
| Distribution: |
| Widespread throughout Asia
in the rivers of Afghanistan to China, Thailand and Borneo.
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| Aquarium
size: |
| 72” x 24” x
24” (180 x 60 x 60mm) |
| Size: |
| 450mm s.l. (standard length
is the measurement from the tip of the snout to the base of
the caudal peduncle). |
| Temp: |
| 20-26°C (67-79°F)
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| pH.: |
| 6.0 - 8.0 |
| Hardness: |
| 4-28°dGH |
| Donation: |
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