Tank Busting Catfish Part Two: The continuing debate, Asian Catfish

by Chris Ralph

ollowing on from my previous article published in the September 2005 edition of Practical Fishkeeping magazine which covered South American species of catfish, I thought that I would pen the following piece on Asian “Tank Busting” species. As with the first article I am merely highlighting the fact that there are many species of catfish which can easily outgrow the largest of aquaria, causing stress to both the fish and owner. As mentioned before I wish I knew the answer as to how to overcome this ever increasing problem being encountered by the hobbyist, the suppliers and retailers. The catfish that you are about to read about are by no means a comprehensive species listing just a few representatives of perhaps some of the catfish encountered from time to time.



Bagarius bagarius

Bagarius bagarius Hamilton, 1822


Bagarius bagarius is commonly known as the Devil Catfish, which is also referred to as Bagarius yarellii. This catfish is quite a rare find amongst shipments of fish from Asia. Bagarius bagarius belongs to the family Sisoridae which are more commonly referred to as Asian Hillstream Catfishes. Within this group of catfish there are around 23 genera and 85 species. As their family name suggests they are naturally found in the fast flowing freshwaters of southern Asia. Most of the catfish within the family Sisoridae are small to medium in size from 6-30cm, with the exception of Bagarius with representative species growing in excess of 2 metres! Bagarius are described as predatory fish quite unlike the other members of the family Sisoridae which tend to be omnivorous. In its natural habitat Bagarius will live under bogwood or logs in fast flowing rivers in wait of its next victim. All of the Hillstream Catfishes are able to inhabit mountain streams by virtue of the fact that the skin on the undersides of their bodies is adapted by being corrugated thus acting as an adhesive attachment to rocks and stones. In addition to the skin being corrugated or folded another factor making these fish better able to withstand the strong water currents they have flattened heads. It is generally documented that most of the representative species of sisorids have a ventrally positioned mouth, allowing them to rasp algae from the substrate (which is not the case with Bagarius bagarius).

I recently had the pleasure of looking after one of these magnificent catfish. I am quite a fan of large catfish as I am sure that those of you who know me appreciate, the problem being the eventual size that this fish can attain…I really could not accommodate a fish that might eventually grow to 200cm (or around 79” in old money). That said I am pleased that I have been able to observe this fish. This fish has evil written all over its face, it watched every move that I made whilst in the fish house and no matter where I was I could sense this fish watching me. It is a fish that does not like to be watched whilst it feeds, so you have to try to be out of eye-shot in order to see it feed. Very much a predator in its natural environment, it will however, take dead foods in captivity. This fish ate almost anything on offer including cockles, whole prawns, mussels, dead fish and large earthworms. It is for this reason that this catfish leads a solitary life, as I would not risk housing any other fish with it.

When keeping the Devil Catfish it is essential to provide the fish with oxygen-rich water due to the fact that these fish are from highland streams. I personally found it essential to provide good filtration and water movement in order to keep this fish in optimum condition. Regular 25% water changes are also appreciated by this catfish, and I always carry these changes out weekly and certainly no longer than fortnightly. Other water parameters such as pH and hardness are not as important as good water circulation and aeration, but nevertheless are still of importance. I found that this catfish will tolerate lower water temperatures than most other species of catfish due to the fact that its natural environment is cooler. I kept the Bagarius at around 22ºC. I have to admit that this is a magnificent catfish to observe, but be warned that they will eat anything small enough to fit inside the enormous mouth that they possess. Finally perhaps it is just as well that these fish are rare amongst catfish imports, as in the wrong hands it could do untold damage to other fish and rapidly outgrow small accommodation.


Scientific name: Bagarius bagarius

Common Names: Devil Catfish
Family: Sisoridae
Synonyms: Pimelodus bagarius, Bagarius yarellii, Bagarius lica, Bagarius buchanani

Natural Habitat: India, Burma, Thailand, Vietnam, Sumatra, Borneo
Aquarium size: For a juvenile catfish a minimum size of aquarium would be 36” x 18” x 18”, for a semi-mature specimen of up to 36” I would suggest at least a 72” x 36” x 36” and for an adult sized fish a large public aquarium!
Temperature: 18-25ºC or 64-77ºF
pH: 6.5-7.8 although it is documented that pH 7.0 is optimum.

Hardness: It is documented that juvenile specimens prefer hardness up to 12ºdGH, but that adult fish can tolerate a hardness of up to 30ºdGH.
Sexual Differences: There are no documented or observed external sexual differences.
Diet: As its common name suggests this truly is a demon amongst the fish world, requiring meaty foods at all times. In the wild this fish would predate upon smaller fishes, but in an aquarium it can be persuaded to feed upon cockles, mussels, whole prawns, dead fish and earthworms. It is also documented that this catfish when kept with fish bigger than itself it would eat their scales.
Breeding: There are no known records of this catfish having been bred in captivity, most likely due to their adult size and size of aquarium/tropical pond required for them.
Compatibility: This really is a fish destined to live a solitary life due to the fact that I am convinced that it would eat just about any other occupant that it could fit inside its mouth.
Colouration: This catfish is quite attractively marked. The base colour of the body of this fish is light brown with dark brown to black mottled markings over the eyes, around the dorsal and adipose fins and at the base of the caudal peduncle. The fins share this mottled pattern of markings.


Hemibagrus wyckioides

Hemibagrus wyckioides Fang & Chaux, 1949


Asian Red Tailed Catfish
When choosing this catfish I thought that I would be writing about a fairly straightforward catfish! How wrong could I be firstly the little beast that I was keeping in the fish house has changed its name from Hemibagrus nemurus to Hemibagrus wyckioides, and reading a little more about this fascinating catfish I find that it can attain lengths up to 950mm or 38”! So how did I end up with this catfish I here you ask? I was shown a listing of fish that were available from a wholesaler and knowing that a good friend of mine Daphne Layley had previously asked me to look out for a Hemibagrus wyckii, I duly ordered two specimens to be collected the following week. I arrived at the shop to collect the fish as planned to find from quite a distance (I was at least ten feet away from the tank that the bag was floating in) that there were not two H. wyckii as expected but two of what I thought were H. nemurus (now H. wyckioides)! I must admit to being more than a little disappointed at the time, but took the fish anyway.

The following week the wholesaler was visited by my friend who informed him of the mix up. The wholesaler said “But you don’t know anything about catfish, and I thought that nobody would notice”, to which my friend replied “I know, but my customer does”! Apparently the wholesaler was a tad embarrassed and has promised to replace the fish for me at some stage (after two years I am still waiting!). I subsequently re-homed one of these catfish to some very good friends on the Isle of Wight, whilst in the remaining catfish has been relocated to one of Daphne’s tanks in her fish room.

I have to say that this is a catfish full of character, but one that is also purely evil. It looks at you as if butter would not melt in its mouth, but turn your back and it is probably the most mischievous fish that I have had the pleasure to keep recently. This catfish is constantly rearranging the décor in the tank, one day the aquarium sand (BD Aquarium Sand) is piled up against one end of the tank the next you cannot see through the front glass! This catfish will eat literally anything that I care to feed it ranging from earthworms, cockles, prawns, mussels etc to catfish pellets and floating food sticks. In some respects I will be sad to see the fish go but I know that it will have much larger accommodation than I can provide for it at present. As most of you reading this will realise this catfish is not one to be taken lightly, and is not one for the novice fish keeper.

Anyway I digress, back to the confusion over the naming of this catfish. Those of you who surf the web will no doubt have come across many sites listing or referring to our favourite subjects “Catfish”, this is where some of the confusion certainly on my part sets in. My first encounters with this catfish (too many years ago to remember now), were when I saw the odd specimen in a retailers tank labelled up as Mystus nemurus, how things have changed. At one time these catfish were compared to the Red tailed catfish – Phractocephalus hemioliopterus “The Emperor of the Amazon” as being the poor man’s cousin. At the time it was thought that H. wyckioides only grew to around 300mm or 12” how naive we were. As the years have passed by this catfish has seen some name changes from Mystus nemurus to Hemibagrus nemurus (or so we thought), to what we now know as Hemibagrus wyckioides; hence the confusion! To further add to this confusion Hemibagrus nemurus is a valid species but differs from Hemibagrus wyckioides in that it does not posses the red coloured tail and has a more flattened head, shorter adipose fin and filamentous extensions to the dorsal and caudal fin rays.

In its natural habitat H. wyckioides is found at irregular depths usually over rocky substrates in large upland rivers. It is documented that this catfish reproduces in its local environment and enters the flooded forest during the high water season which is usually between July and October. This catfish is a predator feeding upon a diet that includes prawns, insects, fish and crabs in its natural habitat. This catfish has the reputation of being one of the most (if not the most) aggressive freshwater fish in the world. This catfish has the ability to bite, hence the reason why in captivity this catfish is ultimately destined to a life in solitary confinement, for if it is kept with other fish the most likely outcome is that they will eventually form part of its diet. As with all large species of catfish (or any other fish for that matter) good water quality and general aquarium husbandry are paramount to the successful keeping of this fish. Water changes should be performed at least weekly to maintain good water quality. This catfish prefers good water movement which can usually be provided by using adequately sized external and or internal power filtration. Finally this catfish is described as being the largest bagrid in Asia reaching weights of up to 80kg!


Family: Bagridae

Sub-Family: Bagrinae

Description: The base body colour of this catfish is light grey/brown with a greenish tinge. The lower half and underside of the body is whitish in colour. The caudal fin in adult specimens is whole or partially coloured bright red. Juvenile specimens have a whitish coloured caudal fin. The dorsal fin has 1 spine with 7-8 soft rays. The anal fin has 12-14 soft rays. The adipose fin is described as being long with a gently sloping anterior margin. The maxillary barbels usually reach to the middle of the base of the adipose fin, although the barbels sometimes extend beyond this point. The head is described as being flat as opposed to being conical with a short occipital process not close to the basal bone of the dorsal fin.

Common Names(s): Asian Red Tailed Catfish, Common Baung, Pla Kayeng Thong, Trey khya, Asian redtail catfish.
Synonyms: Macrones wickioides, Macrones wyckioides, Mystus wyckioides, Mystus wyckoides.

Natural Habitat: Asia: Mekong, Chao Phraya and Xe Bangfai basins; Cambodia, Thailand river systems, Malay Peninsula, Sumatra, Borneo and Java.
Size: 950mm or 38” SL (although 1300mm TL is suggested)
Temperature: 19-29ºC
pH: 6.0-8.2 (although pH 6-7.6 seems to be preferable)

Diet: Whilst this catfish is best described as a predator/carnivore in its natural habitat feeding on fish, insects, crabs and prawns; in captivity this catfish will feed on mussels, prawns, pieces of fish, earthworms and will even take prepared foods such as catfish pellets.
Breeding: There are no known reported aquarium spawnings of this catfish, most likely due to the eventual size that these fish attain and their aggressive nature! The males are said to possess a genital papilla just in front of the anal fin.


Ompok bimaculatus

Ompok bimaculatus Bloch, 1794


Ompok bimaculatus
- Two-spot Glass Catfish, Glass Catfish or Butter Catfish.

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. This particular species of catfish 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 catfish are also found in canals and inundated fields into which these catfish move during the flood season. They 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 this species. 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!

Scientific Name: Ompok bimaculatus

Common Name: Two-spot Glass Catfish, Glass Catfish or Butter Catfish
Family: Siluridae or Sheathfishes

Size: 450mm SL (standard length is the measurement from the tip of the snout to the base of the caudal peduncle).
Synonyms: Silurus bimaculatus, Callichrous bimaculatus, Pseudosilurus bimaculatus, Ompok 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.

Natural Habitat: Widespread throughout Asia in the rivers of Afghanistan to China, Thailand and Borneo.

Aquarium Size: 72” x 24” x 24”
Temperature: 20-26°C

pH: 6.0-8.0

Hardness: 4-28°dGH
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
Diet: 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.
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.
Compatibility: 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.

Colouration: 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 name Ompok bimaculatus!
Body: 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.


Pangasius hypophthalmus

Pangasius hypophthalmus Steindachner, 1878 (Sauvage, 1878)


Pangasius hypophthalmus is a catfish which should never be imported due to the eventual size that it can attain, and the fact that it is a very nervous and skittish fish, which does not fare well in the confines of cramped aquaria. All too often this catfish is offered for sale as a juvenile fish at around 75-100mm and is quite often labelled as Pangasius sutchi or Iridescent Shark. A couple of years ago whilst on a day out with Kate looking at some aquatic retailers we were horrified to find that this catfish was being offered as the fish of the week on a buy one get one free basis. Needless to say we shall not be venturing back to that retailer. If only these catfish remained small and manageable, but alas they do not.

These catfish are bred commercially in large ponds for the aquarium trade, which begs the question why? Obviously there is a demand or else this trade would not exist, how we control the importation of these fish is another story! Who in their right mind would want to keep a catfish that is capable of weighing in excess of 44kg? There is also an albino form of this catfish which is also offered for sale. It is documented that this is a migratory species of catfish moving upstream to spawn in May-July. This fish has been introduced to other countries other than those documented below which include Bangladesh, Philippines, Singapore and Taiwan.

Scientific name: Pangasius hypophthalmus
Common names: Iridescent Shark, Sutchi catfish or Pla Sawai
Family: Pangasiidae
Size: 1300mm or 52” SL (standard length is the measurement from the tip of the snout to the base of the caudal peduncle).
Synonyms: Pangasius pangasius, Helicophagus hypophthalmus, Pangasianodon hypophthalmus, Pangasius pleurotaenia, Pangasius sutchi
Natural habitat: Southeast Asia namely the Mekong, Chao Phyra and perhaps Mekong basins; Thailand, Laos, Cambodia and Viet Nam. It is documented that this catfish has been introduced into additional river basins for the purposes of aquaculture.
Aquarium size: As large as possible but as an absolute minimum for a 450mm specimen I would suggest a 72” x 24” x 24” aquarium, even though I do not advocate the keeping of these catfish.
Temperature: The ideal temperature range is 22-26°C
pH: The ideal range is 6.5-7.5
Hardness: This catfish is tolerant of a wide range of hardness from 2-29°dGH
Sexual differences: It is documented that the males have darker stripes and are more slender than the females.
Breeding: There are no known records of aquarium spawnings of this catfish, which is most likely due to the adult size of these fish and the enormous size of aquarium required. To be honest it is quite a relief that these fish have not been bred in aquarium conditions.
Diet: This catfish is best described as being an omnivore feeding on a mixed and varied diet that includes catfish pellets, catfish tablets, frozen bloodworm, floating food sticks and vegetable matter to name but a few.
Compatibility: Whilst this catfish is fairly peaceful avoid keeping it with small fish as they will eventually appear on the menu. It is best to keep this catfish with other large fish avoiding those species that are too boisterous.
Colouration: The fins of this catfish are dark grey or black in colour. Juvenile specimens are described as having a black stripe along the lateral line with a second long black stripe below the lateral line. Adult fish are described as being uniformly grey in colour. These catfish have a dark stripe on the middle of the anal fin and a dark stripe in each of the caudal lobes.
Body: The body is best described as being elongated. The position of the mouth is described as being terminal. There are 6 branched dorsal fin rays and the pelvic fins have 8-9 soft rays. The gill rakers are described as being normally developed, with small gill rakers being interspersed with larger ones.


Hemibagrus wyckii

Hemibagrus wyckii Bleeker, 1858


Another Asian species, this fascinating catfish has pure evil written throughout its body. Hemibagrus wyckii belongs to the family Bagridae and is naturally found in the freshwater rivers of Thailand, Sumatra and Java. This particular species is capable of attaining a length of 710mm SL (standard length), and is therefore best suited to the confines of large aquaria or dare I say it public aquaria. Hemibagrus wyckii shares a similar name with Hemibagrus wyckioides (see information on Hemibagrus wyckioides) which sometimes causes confusion even though the two fish are distinctly dissimilar. This catfish is documented as inhabiting creeks, lakes and rivers in its natural habitat, and is said to be found or restricted to the middle reaches of these environments. In the wild this catfish feeds on insects, prawns and other fish. In its native countries Hemibagrus wyckii can be found offered for sale in the local fish market as food for the local population.

When providing hiding places they should be firmly positioned within the aquarium and preferably sealed in place with aquarium sealant. Heater guards should also be used in order to protect both the fish and the heater itself from damage. This catfish is very much a predator if ever there was one, and is capable of crushing its prey to almost paper thin proportions with its powerful jaws. I have heard of one crushing the head of a dead Synodontis before swallowing the fish whole! Cover glasses should be firmly in place as this catfish is very powerful swimming from one end of its accommodation to the other at lightning speeds.

Scientific name: Hemibagrus wyckii
Common names: Crystal-eyed Catfish, Baung Jaksa and Plakotkao
: Bagridae
Subfamily: Bagrinae
Size: 710mm SL
Synonyms: Mystus wicki, Hemibagrus wycki, Bagrus wyckii, Macrones wyckii, Mystus wyckii, Mystus wycki
Natural habitat: Hemibagrus wyckii is documented as being found in Asia namely the freshwater rivers of Thailand, Mekong, Menam, Chap Phya, Lopburi, Kanburi, Meping and Mechan rivers; Sumatra, Java, Cambodia, Beng Cha Prek-tuk-Kampot; Viet Nam, Indonesia and Laos
Aquarium size: Due to the eventual size that this catfish can attain I would suggest a minimum aquarium size of 96” x 24” x 24” or a large public aquarium!
Temperature: 22-26ºC
pH: 6.5-7.6
Sexual differences: There are no known sexual differences although it is generally thought that the females may be smaller and deeper bodied than the males.
Breeding: There are no documented records of aquarium spawnings, which is not really surprising considering the fact that these catfish are not tolerant of one another.
Diet: Hemibagrus wyckii is an out and out predator capable of devouring any fish small enough to fit inside its cavernous mouth. Whilst this statement is true of this catfish in its natural habitat, in captivity it will feed on pieces of fish, whole prawns, mussels and earthworms to name but a few.
Compatibility: This catfish is destined to always live a solitary life within the confines of an aquarium, due to the fact that other fish will eventually form part of its diet.
Colouration: The base colour of the body is best described as being black with a cream coloured coracoidal region. The caudal fin is dark grey in colour with a white to cream coloured edge to caudal fin rays. White coloured markings are present on the tips of the pectoral fins and dorsal fin, and are also present on the anterior edge of the adipose fin.
Body: The body is best described as being depressed and broad. The head is described as being extremely depressed and broad. The dorsal fin spine is described as being well ossified and long with 10-12 serrations on the posterior edge. This catfish has a smooth flat skull roof with the occipital process reaching the basal bone of the dorsal fin. The pectoral fins have 10-11 soft rays; the pelvic fins have 6 soft rays. The caudal fin is best described as being forked.

Photo Credits
Bagarius bagarius
- Asian Exports
Hemibagrus wyckioides -
Johnny Jensen's Photographic Library
Ompok bimaculatus -
Johnny Jensen's Photographic Library
Pangasius hypophthalmus - Leigh Murphy
Hemibagrus wyckii - Chris Ralph


Planet Catfish - www.planetcatfish.com
ScotCat – www.scotcat.com
- www.fishbase.org
Catfish Association Great Britain
Volume 1,
Baensch Aquarium Atlas
2, Hans A Baensch and Dr Rudiger Riel.

Published in Practical Fishkeeping January 2006.


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