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Tank Busting Catfish Part One: The Debate Continues..

Chris Ralph

ollowing on from my learned colleague and fellow catfish enthusiast Daphne Layley’s article in Practical Fishkeeping February 2005, I felt compelled to pen this article in support of what Daf had written. Daf and I have shared many conversations over our 20 plus year friendship which dates back to our days spent serving as committee members of the sadly now defunct Catfish Association of Great Britain. We lost contact for a while but in the last couple of years through our mutual interest and passion for all things catfish, Daf has taken up membership and involvement with the committee of the now recently re-named Southern Counties Catfish Rescue Society (SCCRS), and our conversations have continued to flourish as a result. We have discussed at great length the good and bad points involved with the keeping of large catfish, bearing in mind that over the years both Daf and I have kept a number of large catfish with the needs of the fish being at the forefront of our minds. As many of you are probably aware I am fortunate enough to have a couple of tropical ponds within the confines of my fish house. Over the many years that I have been keeping fish I have been called upon to rescue a few less fortunate catfish, which have been able to live out their final days in the surroundings of a 12’ x 30” x 48” pond (30” being floor to top of the pond depth), an environment which is far removed from their natural habitat, but nonetheless better than that of a 48” aquarium.


Quite what the answer is to the debate of responsible ownership of a fish that can easily attain say 24”, and there are a number of species more than capable of achieving this I do not know. I have personally kept a number of large doradids the biggest of which, an Oxydoras niger (Pseudodoras niger) was 42” in length, I think that you must agree a truly magnificent catfish, but one that most fishkeepers would not be able to accommodate due to space and or money. I must say that I have been very fortunate to be able to have kept a number of large catfish live to maturity and beyond. Many years ago some other friends and I discussed the idea of people having a licence to keep all big catfish and any other large fish for that matter. Would it be a licence that the responsible person would have to pay for and produce at a retailer after their facilities had been inspected by another responsible person? How would the facilities be policed in order to ensure that the accommodation was still suitable for the fish being kept some months or even years down the line? How would you stop the fish being given to someone else when for whatever reason its original owner had to part company with it? The list of questions and the debate is almost endless, the answer lies out there somewhere; although how much longer can the hobby and the trade who potentially are at the brunt of it all continue to allow these tank busting fish to be imported?

On a personal level I was very fortunate to visit Peru with a number of friends from the Catfish Study Group (UK) in July 2000. During my two and a bit week stay I was not only to be able to visit a number of different habitats in order to collect fish and enjoy the company of some really good friends, but I was able to experience first hand how our truly delightful hobby impacts upon the local population of people in Peru. I was able to meet a number of exporters as well as some of the people involved with the collection of our fish. I remember being told think of any species of South American fish that could be found in the rivers of Peru, and our contacts at the exporters could take us there (if only we had the time!) or obtain the fish in question for us. I know for a fact that if the organised hobbyists along with the trade said “Right we will not import any tank busting fish in the future” that because of how things work abroad and the fact that many livelihoods depend upon the tropical fish industry, that we would still see some of the unwanted species being exported, but possibly under the guise of a new name or indeed new species in order to attract orders. You would also see unwanted species being shipped to make up the orders as substitutes for fish that were not available at the time of ordering. In truth there is a lot of education required both at hobbyist level and at trade and exporter level. Quite how we achieve this I do not know. I must stress that I am not here trying to give the honest trade bad press, as I am merely expressing my thoughts out load so as to speak. I have a number of very good friends involved in both the retail side of our hobby and also within the wholesale trade, and I know how hard they work to get things right and make their businesses work. There are unfortunately in every walk of life those people who do not care or give a damn so long as they either make a living selling these fish, or those that keep the fish that they want to in less than ideal conditions, to these people I do not apologise for my thoughts and comments.

To further back up the information given in Daphne’s article I thought that I would put together some information on some of the larger South American catfish, some of which I have had the true pleasure of owning or perhaps looking after is more appropriate! Obviously I would be one of the first to obtain a licence in the future in order to keep some of my favourite larger catfish, although I have to say that personally these fish should remain in their natural habitat! This fact is borne out after seeing the body of a Red tailed catfish in the fish market in Iquitos, Peru, which would have been in excess of 72” long had its head still been attached to its body, I rest my case! As promised please find the following information on a few of my favourite tank busting catfish.


Oxydoras niger (Valenciennes, 1821)


Oxydoras niger


Common Names: Mother of Snails Catfish, Ripsaw Catfish & Black Doradid
Family: Doradidae
Synonyms: Doras niger, Doras humboldti, Pseudodoras niger, Corydoras edentatus, Rhinodoras niger, Rhinodoras prionomus, Rhinodoras teffeanus.
Water conditions: pH 6.0 to 7.8 with up to 25 dGH hardness
Origin: Amazon region, Peru, Brazil, Rio Purus, Rio Sao Francisco.
Temperature: 70 – 75 ºF
Size: In excess of 36” (one of mine was 42” when it died)
Sexing: There are no known external sexual differences. There are however some thoughts and suggestions that there may be some differences in the shape of the bony plates which extend from the head to the edge of the pectoral fins. It has been suggested that the male has a more pointed plate, whilst the female has a more rounded plate. There is no scientific evidence that is available to support this observation.
Feeding: Readily accepts all manner of prepared foods. Stinking Sinking Catfish Pellets are high on the list, alongside floating pellets and sticks, as well as frozen bloodworm, chopped mussel and earthworms.
Breeding: As yet unknown.
Compatibility: A real “Tank buster” if ever there was one. Quite a character obviously suited to large accommodation especially if keeping a number of fish together. Peaceful towards other fish and members of its own kind.
Suggested Tankmates: Other doradids such as Agamyxis pectinifrons (Spotted Dora), Platydoras costatus (Striped Dora), Oscars and any other fish of a compatible size.
Furniture: Large pieces of bogwood and clean plastic drainpipe of suitable diameter for them to hide under. Ideally heater guards should be provided in order for the fish not to burn themselves.
Comments: The Mother of Snails Catfish is not a very commonly seen doradid, although if you have kept one then it is one that you will not forget in a hurry due to the size that they can grow to These catfish are usually offered for sale as juvenile specimens at around 4” in length. To the unsuspecting aquarist they have probably taken on more than they bargained for! This said if you are a genuine enthusiast you would already know a bit about these fish and their requirements prior to their purchase. The colour of these fish is basically dark brown to black, hence the name Black Doradid. If you own one of these catfish you will know that feeding time can be a rather wet experience, even with tight fitting cover glasses, or in my case an open topped pond! I have lost count of the number of soakings that I have had over the years! I purchased my first Mother of Snails Catfish about twenty years or so ago. The first one that I owned was around 10” long SL (25cm) and very rapidly outgrew a 72” x 18”x 18” aquarium. I eventually purchased a larger aquarium 72” x 24” x 36” and went on to keep this fish for a number of years. When the fish died from a bacterial infection it was almost 28” in length, and would have required an even larger aquarium before too long. This was really the main reason behind the construction of the Tropical Pond, although at present I am not keeping any large catfish. The Mother of Snails Catfish belongs to the Family Doradidae, all of which originate from various locations throughout South America. Occasionally amongst imports of Oxydoras niger there are the odd slightly different specimens which tend to have black coloured fins and a grey coloured body, which are Pseudodoras holdeni. One of the main characteristics of the doradids is the presence of thorn like projections along the side of the body, which are known as scutes. These scutes are very sharp, so care should be taken when moving these fish. Sometimes literature refers to the doradids as “Talking Catfish” due to the fact that they can be heard to make audible noises, almost as if they are speaking to one another. There have been no records of these catfish having been successfully bred under aquarium conditions yet, which is probably just as well!

Pterodoras granulosus
(Valenciennes, 1811)

Pterodoras granulosus



Common Name: Common Bacu
Family: Doradidae
Synonyms: Doras granulosus, Doras maculates, Doras murica, Doras murices
Water: pH 6.5 to 7.5. It is documented that keeping these fish in water with a pH value above 7.5 can cause skin and eye cloudiness.
Origin: Widespread throughout most of the larger river systems of South America.
Temperature: 20 to 24ºC or 68 to 75ºF although slightly warmer temperatures are also tolerated.
Size: Up to 920mm or 36”+
Sexing: There are no reported external sexual differences. My own thoughts are that females tend to be more heavily built or robust than the males, which tend to be slender. There may also be differences associated with the structure of the head as with the Synodontis catfish, but further observations need to be made.
Feeding: Omnivore feeding on a very mixed and varied diet including catfish pellets, earthworms, whole prawns, mussels, floating sticks/pellets and snails. In their natural environment they would feed upon snails, aquatic plants and fruits.
Breeding: There are no known aquarium spawnings of this catfish. This is most likely due to the size that these fish can attain and hence the subsequent size of aquarium in which to spawn them.
Compatibility: Ideally suited to life with other large fish. These catfish are not predatory but would mistakenly take a smaller fish if hungry.
Suggested Tankmates: Other large catfish such as Oxydoras niger, Leiarius pictus, Perrunichthys perruno, Megalodoras urunoscopus, Oscars and larger characins.
Furniture: Large pieces of bogwood are ideal. Large diameter pipe can be used but it should be large enough for the catfish to easily fit in without becoming stuck. I created two shady areas within my tropical pond, by covering the ends with decking, where these catfish preferred to hide until feeding time.
Comments: The Common Bacu or Pterodoras granulosus is another of my favourite large catfish, which I have had the pleasure to keep. At one time I had three of these “Gentle Giants” housed within my 12’ x 3’ x 4’ tropical pond. They varied in size from approximately 600mm (24”) to 900mm (36”). My observations of these fish suggested at the time that I had two females and one male, as two were rather fat whilst the other was more slender. I did not see any obvious signs of spawning activity, but these catfish were quite happy to swim around the pond together. Whilst fish collecting in Peru, we caught a couple of these catfish on rod and line. These catfish were to spend the next few days on board the accommodation for the week, only to be returned to the point at which they were caught originally. I decided that the three specimens that I had at home at that time were enough and that they would be better off swimming in the Amazon! In South America the local inhabitants would catch and eat these catfish, and as you can imagine a large specimen would feed a whole family for a few days. Seeing these catfish in their natural habitat was an amazing experience, one that will live with me for a long time to come. These catfish are found throughout the river systems of South America. The colour pattern of these catfish varies depending upon the location that they originate from. These fish are usually a muddy-brown colour with some darker spots over the body and fins. As they mature the spotting tends to fade. Juvenile specimens tend not to be as dark coloured as adult fish; in fact the two specimens caught in Peru were light brown/tan in colouration. The body of these catfish is best described as being robust. The body is naked i.e. it is devoid of scales, but the skin is very thick and tough. There are between 23 and 28 shallow lateral plates known as scutes along the length of the body. Their eyes are very small in comparison to the rest of the fish and they have three simple pairs of barbels. They have a deeply forked caudal fin, which also helps to distinguish this fish from other large doradids. In their natural habitats these catfish are migratory, shoaling in large numbers as they make their journeys upstream to spawn.

Megalodoras urunoscopus
(Eigenmann, 1925)

Megalodoras urunoscopus



Common Names: Mother of Snails Catfish, Giant Raphael Catfish, and Giant Talking Catfish
Family: Doradidae
Synonyms: Megalodoras irwini
Water: pH 6.5-7.5
Origin: Peruvian and Brazilian Amazon, Maranon and Guianas
Temperature: 22-26ºC (72-79ºF)
Size: 61cm (24”)
Sexing: There are no reported external sexual differences. My own thoughts are that females tend to be more heavily built or robust than the males, which tend to be slender. There may also be differences associated with the structure of the head as with the Synodontis catfish, but further observations need to be made.
Feeding: Their natural diet includes crustaceans such as aquatic snails, which should be included as part of their captive diet. In the aquarium they will feed on sinking catfish pellets, floating food sticks, whole prawns, earthworms, chopped and whole mussel. They also relish sinking tablet foods.
Breeding: There are no known documented aquarium spawnings to date, although there may be some breeding-taking place in Czechoslovakia using hormone inducement.
Compatibility: Ideally suited to life with other large fish. These catfish are not predatory but would mistakenly take a smaller fish if hungry.
Suggested Tankmates: Other large catfish such as Oxydoras niger, Leiarius pictus, Perrunichthys perruno, Oscars and larger characins.
Furniture: Large pieces of bogwood are ideal. Large diameter pipe can be used but it should be large enough for the catfish to easily fit in without becoming stuck.
Comments: This particular catfish is perhaps one of the more colourful of the members of the family Doradidae, and is also one of the larger species hence the common names. This catfish is quite often described as being one of the “Tank Busters” due to the fact that it can grow up to 610mm or 24” standard length (from the tip of the snout to the base of the caudal peduncle). The local name given to this fascinating catfish is “Key-way-mamma” which refers to the common name of “mother of the snails”. The reason for this common name being due to the fact that when a specimen was examined the intestine was lined with large aquatic snails along its length. Some of you reading this information may be wondering why the scientific name for this fish is not Megalodoras irwini, the reason being that the name has been recently changed and that the old name is now a synonym. It has an interesting colour pattern with dark brown markings on a light brown background. The body and head are covered in dark brown to black blotches. The ventral (underneath) region of this catfish has a mottled pattern, which is dark brown in colour. The fins are mottled or spotted irregularly with black coloured markings. The pectoral fins tend to be lighter in colour towards the base and darker towards the edge. The adipose fin is light brown at the top edge of the keel and darker towards the base. Megalodoras urunoscopus has 15-18 lateral scutes that increase in size towards the caudal fin. There are many caudal fulcra or bony plates. There are no plates above or below the caudal peduncle. The adipose is described as continuing forward in the form of a hard keel. This catfish has two pairs of barbels, one pair maxillary and one pair mandibular. Keeping Megalodoras urunoscopus is relatively easy assuming that you have the available tank space in which to keep them at their optimum. Ideally they are best housed in an aquarium which is at least 72” x 24” x 24”. The preferred substrate is sand such as BD Aquarium sand, although rounded gravel can also be used. They tolerate a wide range of water conditions, but do like to be able to hide away. Aquarium décor should include bogwood and if you don’t mind the appearance large diameter pieces of drainage pipe. This species of catfish despite the size that it can attain is really a “Gentle Giant” and can be kept with other large or medium sized fish. They are not commonly available, if you have the space for one or more as they do tend to like their own company, they are well worth obtaining.


Merodontotus tigrinus
(Britski, 1981)


Merodontotus tigrinus



Common name: Tigerstriped Catfish
Family: Pimelodidae
Synonyms: None
Water: pH 6.5-7.5
Origin: Rio Maderia in Brazil, Columbia and Peru.
Temperature: 22-26ºC
Size: 600mm or 24”+
Sexing: There are no known obvious external sexual differences.
Feeding: As these are predatory catfish they prefer meaty foods such as whole prawns, mussels, pieces of fish and earthworms etc.
Breeding: There are no records of aquarium spawnings due to the adult size and price tag associated with these fish.
Compatibility: Not compatible with other pimelodids due to its territorial nature.
Suggested Tankmates: Anything that does not constitute a meal, I would suggest some of the larger Characins as opposed to any other catfish, which may compete for territory. Most enthusiasts would keep this catfish as a single specimen in a display aquarium.
Furniture: Large pieces of bogwood are ideal. Large diameter pipe can be used but it should be large enough for the catfish to easily fit in without becoming stuck.
Comments: This magnificent catfish belongs to the family Pimelodidae, representatives of which can be found widespread throughout the rivers of South America. The original specimens that were caught and described by Dr Britski of the Sao? Paulo Zoology Museum were from the Rio Maderia in Brazil. It was originally thought that this was the only location where this species of catfish was found, however this catfish is known to be collected in Columbia and I personally have experience of Peruvian exporters collecting these catfish in Peru. The original fish were collected in 1978 by Michael Goulding. A publication by Dr Dario Castro of the University of Bogotá in 1984 recorded this catfish as being collected from the lower Caqueta River in Columbia. Merodontotus tigrinus is quite closely related to Brachyplatystoma juruense, but has a longer upper jaw, and the first rays of the dorsal and pectoral fins are described as being flexible and not pungent. Both of these catfish share a similar colour pattern of inclined stripes on the body, although it has to be said that Merodontotus tigrinus is the more striking of the two fish. Brachyplatystoma juruense is quite often referred to as the “False Tigrinus”. The colour pattern is outstanding with a yellow to almost white base colour to the body with black stripes. Most of the fins share this same colour pattern of that of the body of this catfish. In their natural habitat, however they grow well in excess of this size and can attain lengths in excess of 600mm quite easily. This catfish is perhaps one of the most expensive specimen fish from this family of fish. The first specimen that I ever saw back in the mid eighties had a price tag of £1000, and I have recently seen specimens for sale at between £500 and £600. Obviously consideration needs to be given to the size of aquarium in which to keep such a magnificent catfish as this, I would not recommend anyone to keep one of these catfish in anything less than a 72” x 24” x 24”. As well as the size of aquarium good filtration is also very important in order to keep a catfish such as this in perfect condition. I would also suggest that sand such as BD Aquarium sand be used as a substrate for the aquarium. This is a catfish that I have not personally kept which probably has something to do with the high price that these catfish demand. It was whilst on my fish collecting trip to Peru that I found out some little known information about this fish. The exporter in Peru that specialises in large specimen fish such as this informed us that they collect these catfish as juvenile specimens from a local breeding area in the river and grow them on for export. We were informed that when collected at between 50 and 75mm they could be reared successfully in the holding tanks and fed on their favourite food of knife fish. This particular exporter found that when collected at a size of around 300mm they did not fare well and would not feed in captivity. The Peruvian exporter keeps these catfish at his premises for around six months before offering them for sale.

Leiarius pictus (Muller & Troschel, 1849)

Leiarius pictus



Common Names: Sailfin Pimelodid, Saddle Catfish, Painted Catfish, Sailfin Marbled Catfish
Family: Pimelodidae
Synonyms: Bagrus pictus, Leiarius longibarbis, Sciades longibarbis, Sciades pictus, Sciadeichthys pictus
Water: pH 6.2 to 7.5 and up to 18ºdGH
Origin: Widespread throughout the Amazon and its tributaries, South America.
Temperature: 22 to 26ºC or 72 to 79ºF
Size: 600mm + or 24”+
Sexing: There are no reported external sexual differences. My own thoughts are that females tend to be more heavily built or robust than the males, which tend to be slender.
Feeding: Carnivore feeding on a very mixed and varied diet including earthworms, whole prawns, mussels, floating sticks or pellets and catfish pellets. In their natural environment they would feed upon other fish.
Breeding: There are no known aquarium spawnings of this catfish. This is most likely due to the size that these fish can attain and hence the subsequent size of aquarium in which to spawn them.
Compatibility: Ideally suited to life with other large fish. These catfish are predatory and could mistakenly take a smaller fish if hungry.
Suggested Tankmates: Other large catfish such as Oxydoras niger, Pterodoras granulosus, Megalodoras urunoscopus, Oscars and larger characins.
Furniture: Large pieces of bogwood are ideal. Large diameter pipe can be used but it should be large enough for the catfish to easily fit in without becoming stuck. I have managed to create two shady areas within my tropical pond, by covering the ends with decking, where this catfish prefers to hide until feeding time.
Comments: The Sailfin Pimelodid or Leiarius pictus is another of my favourite large catfish, which I have had the pleasure of keeping within the confines my tropical pond. It has to be said that this particular catfish was a real character fish. I kept this catfish for six years, after I was asked by my good friend Giles Barlow of Barlows Aquatic Trading, to rescue this fish from one of his customers’ tanks. When I collected this fish it was approximately 16” long, and it was approximately 28” long when it died, so as you can appreciate this is not a catfish for your average sized aquarium. This catfish is sometimes confused with Perrunichthys perruno (Reticulated pimelodid) and Leiarius marmoratus (Marble antenna catfish). The overall body colour of Leiarius pictus is dark brown with darker spots, with a lighter underside colouration. More noticeable in juvenile specimens this catfish has two pale bands, the first extends from the base of the dorsal fine spine toward the ventral fin, and then laterally along the body to the base of the caudal; the second thinner band lies parallel to the first originating from the base of the third to sixth soft dorsal fin rays. Large round spots can be seen in the dorsal, adipose and caudal fins, whilst the anal and ventral fins have much smaller spots. The barbels have a ringed pattern to them alternating light and dark colouration. With regard to the anatomical characteristics of Leiarius pictus the head is described as being narrow and flattish above. The upper jaw is slightly longer than the lower jaw. The maxillary barbels in adult specimens extend just beyond the dorsal fin; the inner mandibular barbels extend to the base of the pectoral fin whilst the outer mandibular barbels extend to the middle of the pectoral fin. In juvenile specimens the maxillary barbels can be seen to extend well beyond the tips of the caudal fin. This catfish has a large sail-like dorsal fin with 9 – 10 soft rays hence the common name of Sailfin Pimelodid. The caudal fin is described as being deeply forked. As mentioned above there are a number of differences between juvenile and adult fish, such as the fact that the barbels shorten in ratio to body size in adults, and the colour is less intense in adult fish. The lobes of the caudal fin are more rounded in young specimens whilst they are more pointed in adult fish. These catfish are real character fish, but can be very territorial especially towards other pimelodids. My own catfish had a very understanding relationship with a large Oscar, basically if the Oscar got in the way at feeding time, the Leiarius pictus would take the Oscar in its mouth and swim around the pond a couple of times before depositing the disorientated fish in one of the corners! A fascinating catfish to observe and an amazing site to see the barbels protruding from the surface of the water at feeding time. I was able to feed this fish by hand just as long as one of the larger doradids did not spook the fish at the same time. It is documented that Leiarius pictus suffer from claustrophobia caused by the fact that all too often these catfish are kept in accommodation where their maxillary barbels touch the front and back of the aquarium, thus stimulating both barbels at the same time causing the catfish to become confused! If this is the case it has been reported that these catfish will try to exit the aquarium, and it is therefore recommended that tight fitting covers be added to the aquarium. This did not appear to be a problem in my uncovered tropical pond!


I will concentrate on some African and Asian tank busters in order to continue the debate in the second part of my article.


Chris Ralph 26th February 2005
Previously published in the September 2005 edition of Practical Fishkeeping magazine.


Photo Credits:

Oxydoras niger: Danny Blundell
Pterodoras granulosus: Danny Blundell
Megalodoras urunoscopus: Danny Blundell

Merodontotus tigrinus: Chris Ralph
Leiarius pictus: Allan James

 

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                                                                                                                                             Article updated = February 25, 2016
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