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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 bimaculatus.

This 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.

Ompok bimaculatus

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!.

Ompok bimaculatus - head view

Update: Ompok siluriodes was at one time a synomyn for O. bimaculatus but O. siluriodes has a marbled body pattern against the silver of O. bimaculatus.

Two-spot Glass Catfish, Glass Catfish, Butter Catfish

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.

Silurinae

Asia: Indian subcontinent and Myanmar.

450mm s.l. (standard length is the measurement from the tip of the snout to the base of the caudal peduncle).

20-26°C (67-79°F)

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.

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.

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.

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.

Photo Credits

© Beta Mahatvaraj