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 Catfishes

A chaotic biodiversity that is still waiting to be discovered

By Andreas Iliopoulos 

All of us that are involved with fish keeping in captivity are fated to sooner or later handle Catfishes. There are two specific reasons for that, and acquiring catfishes for the first reason usually makes the hobbyist aware of the second.

We use several species of catfishes in our community tanks because these fishes do a lot of work in a closed ecosystem such as an aquarium, so they keep the biological chain in function.

Catfishes collect all the uneaten food from the substrate and consume it. They also play the role of the scavenger and keep our tanks clean of corpses and dead organic materials. Also, catfishes are the ones that maintain the quantity of algae in our tanks and ponds.

In both cases, these kinds of fishes are very important; as uneaten food that is decaying or an excess of algae in the enclosed fragile aquaria system would produce pollutants that would upset the desired balance.

So the first, and main, reason we keep them in our tanks is our need to control the food chain naturally. The second reason has to do with the strange beauty of these species and their odd behavior. Their peculiarity, as well as their importance as animals, makes them a highly wanted addition to a hobbyists’ collection. The rarity of some species – even in their natural environment – and their vast biodiversity makes some aquarists dedicated in keeping only catfishes in their tanks, and some hobbyists develop a manic obsession with the biology of the species, constructing a second hobby within the hobby.

SOME USEFUL INFORMATION ABOUT SYSTEMATIC BIOLOGY OF CATFISHES

Catfishes belong to the large group of OSTEICHTHYIDAE, belonging to the class of Actinopterygii, which means that their skeletons are constructed by bones rather than cartilage or cartilaginous plates. Their fins are vermiculated, in contrast to the fleshy fins with bones that sharks, rays and primitive Coelacanthus and Coelacanth-like fossils have.

They also belong to the order SILURIFORMES, which includes over thirty families and more than four hundred species that inhabit almost all the waters of our planet, as it is shown on Plate 1.

Here, we shall try to uncover as much information as we can about the most abundant families and species in the aquarium hobby. This does not mean that we should disregard the rest of the families and species (see Plate 2. for a detailed classification that has been achieved until today; as every day new species are collected and the research goes on and on).

The most common species of catfishes that are usually seen in community tanks belong to the families CALLICHTHYIDAE (like Corydoras species) and LORICARIIDAE (like Ancistrus species).

In origin tanks that house members of the family CICHLIDAE from the east African rift lakes, we usually see catfishes that belong in the families MOCHOKIDAE (for instance, Synodontis species) and BAGRIDAE (Auchenoglanis species). It is a bit uncommon, though, to find members of the SCHILBEIDE family in such tanks (due to the size of the most of these catfishes) with Victorian cichlids and even more uncommon to see members of the MALAPTERURIDAE, due to their large size and predatory habits (they electrocute their prey).

                                                                                                                           Plate 1. 

Very popular are some members of the DORADIDAE family (like Acanthodoras species) and PIMELODIDAE family (such as Pimelodella pictus, P. maculatus, Phractocephalus hemiliopterus) from the South America region, and PANGASIIDAE (Pangasius species) and SCHILBELIDAE from Asia. Also, very rarely, we find African SCHILBELIDE (as Schilbe intermedius).

Unfortunately, we often times see members of the CLARIIDAE family (Clarias species) in unsuitable tanks. These species grow very large (Clarias batrachus - 50cm, C. gariepinnis - 75cm) and they are usually housed with unsuitable tank mates, on which they satisfy their voracious appetite. The ending is that in these tanks only the catfishes remain, as anything that fits in their mouth will be devoured after a while. Another oddity is that these fishes can breath atmospheric air, and they may live many hours out of water, achieving remarkable records if the humidity is enough for them. It is said that they are the last animals that die in African water pits during the dry season when the savanna becomes parched and kills crocodiles and hippos.

The other families’ members are very, very rare and their appearance is usually witnessed only in tanks of very dedicated aquarists.

Update >

Wolfgang Ros sent us the following information : For current pictures and a short report of clarias batrachus - breeding / mating, please take a look under:

http://community.forenshop.net/forums/index.php?mforum=predatortalk&showtopic=124

My detailed report "Erfolgreiche Froschwels-Nachzucht im Aquarium" (Succeeded walking catfish - mating in the tank) is published in: "Die Aquarien- und Terrarienzeitschrift" (DATZ) 7/04, pages 12-15. Unfortunately only the first section of this report is adjusted to the following Website:

http://www.ulmer.de/artikel.dll?MID=531&AID=20304

Whoever has interest, can order the DATZ 7/04 at the publishing house "ulmer" (for more informations: info@ulmer.de).
 

CALLICTHYIDAE 

This family includes two of the most known subfamilies: the CALLICHTHYINAE and the CORYDORADINAE.

CALLICTHYINAE includes, among others, the genera Callichthys (C. callichthys), Dianema (D. longibarbis, D. urostriata), Hoplosternum (H. littorale, H. pectorale, H. thoracatum variations), while CORYDORADINAE includes 189 Corydoras species, some genera of the Bronchis species (Β. britskii, B. multiradiatus, B. splendens) and species of the genus Aspidoras (A. albater, A. fuscoguttatus, A. menezesi, A. pauciradiatus, A. rochai).

The enormous number of Corydoras species has made the biologist classify them not by name but with a capital C, that represents the genus and a number that represents the species (C 4 for instance, represents Corydoras virginiae, Miguelito Panzerwels).

BIOLOGY 

Most of the members of CALLICTHYINAE family live, feed and reproduce on the bottom or very close to the bottom, and there are only a few exceptions. They detect their prey with the help of their barbells-sensors, so we have to keep them in tanks with very fine quartz gravel or sand as a substrate. Sharp edged substratum will hurt the barbells and damage them. Damaged barbells can cause bacterial and/or parasitic infections that drive the fish to death from starvation or diseases. Lava will irritate the barbells and mouth region of catfishes, so it is not advisable to use it in tanks with these bottom dwellers.

Callichthys callichthys, Dianema and Hoplosternum species are mainly nocturnal. Because of their benthic habits, they are vulnerable to chemical processes (such as anaerobic process and Nitrate (NO3¯) concentrations) that take place in the substrate region of a newly established tank, so it is better to introduce catfishes into well cycled tanks.

FEEDING 

In their natural habitats, catfishes feed upon benthic organisms (worms, eggs, insect larvae and aquatic creatures larvae) and dead organic material from decomposing flesh that they detect with their sensors from the substrate (bottom feeders).

In captivity we should provide them foods with high concentrations of proteins not of mammalian origin. Live foods are also essential for their well being and breeding. Suitable foods for this purpose are Mysis shrimp, Daphnia, Cyclops, Microworms, black and white Mosquito larvae, Glass worms, Artemia salina etc. Dry foods, freeze-dried varieties and tablets or pellets are pleasantly accepted from them as well. Always keep in mind to dampen tablets and pellets before feeding.

BREEDING 

Catfishes are oviparous (lay eggs) and they spawn on the substrate, near it or under the water surface vegetation. In nature, the spawning period is usually during the rainy season, as chemical compositions of waters are different due to nutritious materials that are washed into bodies of water. During this period, there is plenty of food for adult fish and their fry and also plenty of food for their feeders (insects, for instance). In captivity we may reproduce these conditions as closely as possible.

Callichthys callichthys and Hoplosternum species have a very interesting breeding behavior that closely resembles the breeding technique of BELONDIDAE. The males construct a bubble nest under leaves of water plants. The females deposit their clutches inside and the males fertilize them and keep nests, eggs and fry safe by chasing away any intruder. The clutch size differs from species to species and is proportional to the size of the breeders. They may vary in number from 100 to 500 eggs. The incubation period may last three to four days and is dependant upon water temperature. The larvae are not very big, so their first food must be their size (Microworms, newly hatched brine shrimp). Later, they can be fed and weaned with Cyclops, Daphnia and fine dried or freeze dried foods.

Corydoras also feature a breeding ritual. Several males chase after one heavy bodied female. The females form their pelvic fins as a basket and carry the eggs to the chosen place to deposit them. One male forms a T position with the female, stimulating her with his barbells on the ventral region. The whole thing looks rather like a comic dance with grotesque jumps.

Proportional to the size and the species, they lay 100 to 200 eggs on the substrate, driftwood, stones and aquatic plants. In a breeding tank we may see the clutch glued on the glass of the tank near the bottom. It is good to remove the parents from the breeding tank after spawning as they are not involved with incubation or any parental care, and may even eat their eggs. When we desire to breed Corydoras species in captivity it is better to keep males and females separately, feed them heavily with live foods, and when they are well conditioned we must introduce one female for 4 or more males in the breeding tank.

The most common Corydoras in community tanks are C. aeneus and C. paleatus (both plain and albino forms). Hobbyists though, prefer C. julii, C. melanistius melanistius, C. m. brevirostrum, C. rabauti (“myersi”), C. adolfoi, C. melanotaenia, C. trilineatus, C. barbatus, C. reticulatus, C. haraldshhutzi, C armatus, C. panda, C. sterbai, C. metae, C. evelynae, C. eques, C. arcuatus, C. elegans, C. pygmaeus etc. Other Corydoras and Aspidoras species are rather uncommon, if not rare, in aquaria.

WATER CHEMISTRY

The fishes of this family live in South America. The waters of this region feature a variety from the very soft and acidic black waters of Amazon and Rio Negro (2,0 dGH, pH even < 6,0), to neutral and even slightly hard and alkaline white waters (up to 25 dGH and a pH up to 8,0).

They do not appreciate high temperatures, as the temperature near the bottom of the water body is cooler and they have higher dissolved Oxygen concentrations.

OVERALL 

The fishes of this family are very nice tank residents. Their small and medium size, make them suitable tank mates for nearly any community tank. The bigger species grows up to 18 cm (C. callichthys), but usually they reach 12 cm (Hoplosternum species). The smaller Corydoras species grow up to 2,5 cm (C. pygmaeus) while the larger reaches nearly 12 cm (C. barbatus). It is not a good idea to house these fishes with large aggressive tank mates like Astronotus ocellatus or other large Central and South American cichlids. Other benthic species that are incompatible with these are the Asian Botia species, as their food and feeding habits are very similar so there would be much competition between them.

Their helpfulness as garbage controllers and scavengers and their cute schooling behavior (never house, for instance, less than 6 to 8 Corydoras per tank) and their oddities have made them a must for community tanks.

LORICARIIDAE

LORICARIIDAE family includes at least 7 subfamilies with over 130 genera. The most known and popular are: ANCISTRINAE, HYPOPTOPOMATINAE, HYPOSTOMINAE and LORICARIINAE. In subfamily ANCISTRINAE belong the genera of Ancistrus species, Acanthicus species, Baryacinstrus species, Chaetostoma species, Dekeyseria species, Lasiancistrus species, Leporacanthicus species, Lithoxus species, Hemiancistrus species, Hypancistrus species, Panaque species, Pecoltia species, Pseudacanthicus species, etc. Members of the subfamily HYPOPTOPOMATINAE are the species of the genera Hypoptopoma, Microlepidogaster species, Otocinclus species, Otothyris species, Parotocinclus species etc. HYPOSTOMINAE subfamily includes the genera Cochliodon, Glyptoperichthys species, Hypostomus species, Liposarcus species, Monistiancistrus species, Pterygoplichthys species etc. And in the subfamily LORICARIINAE belongs species of the genera Farlowella, Loricaria species, Ricola species, Rineloricaria species, Sturisoma species, Sturisomatichthys species, Lamontichthys species etc.

Because of the extremely large number of Loricariid species, their classification is being made by the capital letter L and a number that follows. L represents the family and the number represents the species (for instance L 015 represents Pecoltia vittata, known as Rio Xingu Pecoltia). German systematic biologist used, until recently, LDA numbers (“DAS AQUARIUM” publications) and Brazilian exporters TR numbers, so the confusion was major. During the last few years only L numbers and sometimes LDA numbers are used so their taxonomy became simpler.

BIOLOGY

The members of the family are oviparous (lay eggs). They live in “black” waters as well as in “white” ones in the river systems of South America (Amazon basin, Rio Purus, Rio Negro, Orinoco, etc.). Many of them live in very soft (up to 2,0 dGH) and acidic (pH even low as 5,0) waters, several others in neutral waters and some others in slightly to moderately hard (10 – 12 dGH) and slightly acidic waters (pH 7,5). Their natural biotopes are cool, fast flowing waters rich in dissolved Oxygen, while some prefer warmer and still water bodies. Many prefer the submersed root formations of aquatic or water friendly tropical trees and driftwood that enhances the water with tannic and humid acids and color. Some, like the Ancistrus dolichopterus, make their nests in caves of sunken bogwood, while others use crevices of stones, as Hypancistrus zebra does; and some others dig their nests in the mud of riverbanks as male Liposarcus anisitsi do. During the dry season, these kinds of nests they may be found above the water level, but the moisture keeps the animals wet and safe from drying out. The accurate recognition of the species helps us to provide them the suitable water parameters and the right aquascape for their well being and breeding in captivity. The size of these species differs, so we may find very small species 4 cm and under (Otocinclus affinis), while some others can reach 45 cm (Glyptoperichthys gibbiceps) and some others may grow over 50 cm as the Liposarcus multiradiatus.

FEEDING

Feeding habits of these animals are as diverse as their origin and environments. There are completely herbivorous species (vegetarians) that prefer algae, fruits from the rain forest trees; omnivorous species that utilize whatever is abundant at any season and is considered food and some carnivorous species (flesh eaters) that eat worms, small crustaceans, plankton and invertebrates. As was said above, the recognition of any particular species we want to keep is very important, as feeding them is dependant on the accurate recognition of the species. In captivity, we must provide herbivorous species with green foods such as algae, spinach, spirulina, zucchini and broccoli, while we must feed the carnivores foods rich in proteins; live foods as Whiteworms, black mosquito larvae, Artemia salina, Daphnia, Cyclops etc. and high quality freeze dried or dried foods. Pellets and tablets must be moistened before are given and, because most of the species are nocturnal, it is advised to be fed right after the tank’s lights goes off. The presence of driftwood, mopani or bogwoods is essential in the tank, as they love to chew wood either for constructing nests or even for digestion, as greens are hard foods to be digested (same thing as with chickens that swallow little pebbles).

BREEDING

Spawning some of these species might be very easy (as Ancistrus dolichopterus or Sturisoma species), as long as the animals receive appropriate food, aquascaping and water chemistry. A. dolichopterus is a prolific spawner in a neutral to moderately alkaline (pH 7,0 – 8,3) and moderate to very hard (anything from 6,0 to 50 dGH) water (from personal observations). They demand clean, fast moving, slightly cool (not more than 26° C for spawning stimulation and no more than 24° C for keeping and growing them) water. They also need driftwood with holes, which the male will dig out and size as it likes and utilize them as its spawning site and for egg and fry deposit. They prefer vertical deep holes away from the current, and it is better not to have more than 3 females per male as the females become rather aggressive and competitive among themselves when attempting to enter the male’s spawning site.  Because they do not harm their fry, it is common to see adults with several generations of fry (newly free swimmers to semi adult fish) in the same tank. The male accepts ripe females into the nest only for depositing the eggs, and then they are chased away. A male can mate with two different females at about the same time (when one leaves the nest after depositing its eggs, the other enters and deposits its own). The fry are quite large when they abandon the nest and eat microorganisms from the substrate, but they accept live foods; and artificial foods are very easily taken, as well. They have a regular growth rate and if they are fed heavily and we are performing frequent partial water changes (15% daily) they grow rather fast (personal observations). They love spinach and spirulina tablets, but they prefer half - boiled zucchini and broccoli. There is sexual dimorphism as males develop a dense tuft of long horn-like fleshy bush on the front of their heads, but females don’t.

IN GENERAL

The members of the subfamily are the most appreciated between aquarists. The most popular are the species of the genus Ancistrus (A. dolichopterus, A. sp. cf. temminckii etc.), several species of the genus Chaetostoma (for instance Chaetostoma leucomelas), and species of the genus Peckoltia (Peckoltia vittata – known as L015). Some hobbyists prefer the larger species of this genus as Panaque nigrolineatus, P. suttonorum and others.

Among the members of the subfamily HYPOPTOPOMATINAE more common are the small species of the genus Otocinclus (as O. affinis, O. vittatus, O. flexilis etc.). The dedicated aquarists prefer more rare species like LDA 023  - Otocinclus species or Venezuelan Pecoltia and Hypoptopoma species.

HYPOSTOMINAE

Many very popular species belong to this subfamily, and are common in many aquaria, like the species of the genus Glyptoperichthys. They also lay eggs and they are rather omnivorous, although they take a good care of the algae in community tanks with large cichlids. Hypostomus plecostomus are very common (in their regular, xanthic and albino form) and Pterygoplichthys gibbiceps are a must for big tanks. They do not harm plants – as a rule with exceptions, of course – but their large size make them clumsy in planted tanks, while swimming between them, when they are trying to find a good place to rest or while they are “redecorating” their tanks according their own desires. Although they are nocturnal, they easily get adapted in diurnal action when they feel safe in their tank. In this case, they will swim up to the surface to consume flakes with other surface feeder fishes. They may reach a length of 50 cm. Hobbyists prefer rarer species such as Glyptoperichthys species cf. lituratus, Hypostomus regani, Liposarcus anisitsi (Snow king pleco), Cochliodon cochliodon. They accept any kind of foods (live, frozen, freeze dried, tablets, pellets, flakes and fresh fruits and vegetables). There are not many things known about their reproduction, but they possibly have the same demands and techniques as the members of the ANCISTRINAE and the LORICARIINAE subfamilies’ species.

LORICARIINAE

This subfamily includes very many species. Among these species, some are very popular in the aquaristic community. The most abundant in home aquaria are the members of the genera Sturisoma (as S. aureum), Farlowella (as F. acus, F. gracilis), Rineloricaria (as R. lanceolata, R. teffeana, R. microlepidogaster, R. fallax). The most beautiful of them are Rineloricaria heteroptera, R. morrowi, Sturisomatichthys leightoni, Lamontichthys filamentosa and they are preferred by hobbyists. There is sexual dimorphism and the males protect the nests (if they use nests) and their eggs. The species of the genus Sturisoma (like S. aureum) spawn on open surfaces while many species of the genus Rineloricaria (as R. fallax) use holes and burrows of sunken driftwood as spawning places. They prefer cool water and the incubation period last for about a week in 24° C. They may produce 40 – 200 eggs (depend on the species and size). The color and the shape of their eggs vary from yellowish round to brown yellow ellipsoid eggs. The fry can be fed on live foods although they’ll prefer awfwuchs. They love peas, spinach, zucchini, broccoli, moistened spirulina tablets or even flakes. They are very beautiful and interesting fish species. They fit in any planted (not heavily planted) tank, as long as there are no extreme water parameters, their tank mates are peaceful, and the water temperature is between 23° C and 26° C. They also like chewing on wood, so some pieces of driftwood, mopani or bogwood must be added in their tank.

DORADINAE – GENERAL

This catfish family includes the well-known genera Acanthodoras, Agamyxis, Amblydoras and other less known ones. They prefer slightly acidic to neutral waters (pH 5,8 – 7,5) with rather low to medium hardness (0 – 25 dGH), as their natural habitat is in the Amazon outfall region, Equador, Guyana and Colombia. They may be included in community tanks with peaceful tank mates. They are peaceful nocturnal animals themselves. During daytime, they hide under stones or logs and they can tolerate very low temperatures (Agamyxis pectinifrons is said that it can live in 15°C). The males probably build bubble nests under surface aquatic plants (as said by Hancock), where females will deposit up to 2000 eggs. They do not need taller than 30 cm tanks to be kept in, but they do prefer a dark, fine substrate and a lot of hiding places and an average plant growth. Amblydoras hancockii and Platydoras costatus are very popular and easy to be found in the market. Their marketability, though, is rather low due to their nocturnal habits.

MOCHOCIDAE – GENERAL

This family includes at least 10 subfamilies with more than 150 species. Two of the subfamilies are very well known among aquarists involved with east African cichlids. These are CHΕILOGLANINAE and MOCHOCINAE. Within CHΕILOGLANINAE belong the species of the genus Cheiloglanis, while within the subfamily MOCHOCINAE belong the very popular species of the Synodontis genus, and the Hemisynodontis, Mochokiella and other species. From the genus Synodontis, many species are preferred tank mates for Rift Lakes’ cichlids and especially for Tanganyikans, as eleven of the species are endemic to the lake (for instance S. nigriventris, S. notatus, S. decorus, S. angelicus etc.) There is also one endemic in Malawi (S. njassae). The most of them reach a length of about 20 cm. The larger are S. nigramaculatus, S. obesus which they grow to 40 cm and even bigger is S. angelicus (attains a max. size of more than 55 cm). The smaller do not grow larger than 15 cm in length and S. contractus reaches just 7,5 cm. They are mainly nocturnal (some, like S. congicus are rigidly nocturnal) and lay eggs. Some species have developed the cuckoo bird technique for their breeding.

 They lay their eggs near the spawning mouth brooders. The female mouth brooders carry their eggs as well as its eggs, but the catfish fry hatch earlier and they are big enough to eat either the cichlid eggs or the cichlid fry, so cichlids give birth only to well developed “catfish” fry. Such species are S. multipunctatus and S. petricola. Females carrying cichlids may be in danger from these incubations as the spines of baby catfishes are venomous and can become lethal to the cichlids. This technique gave the name “cuckoo catfishes” to such species, and keepers describe it because it happened in their tanks. The rest of the breeding behavior of these animals has not been observed in captivity. It is supposed that they spawn in crevices and caves, where two animals of the opposite sex fit in to spawn.

Most species in the trade are wild caught ones, but as soon as they adapt in captivity they can accept any type of foods, even flake food. Common species in aquaria are S. nigriventris, S. decorus, S. schoutedeni, S. flavitaeniatus, S. brichardi, S. eupterus, S. notatus, S. brichardi, S. multipunctatus etc. Suitable for Tanganyika community tanks are the small Tanganyikan species like S. petricola, S. multipunctaus, S. constractus and S. nigriventris and S. njassae is preferred for the Malawi community. Some of the species are aggressive and territorial with conspecifics (S. notatus), so we have to be careful when we introduce them in community tanks. The species of Hemisynodontis, Mochociella and Cheiloglanis are rather uncommon in captivity.

PANGASIIDAE – GENERAL

These species are very common in tanks and they have won the title of “the most miserable species in the hobby”, as they are usually kept in very small aquaria with unsuitable tank mates. The reason for that is their size. Pangasius hupophthalmus for instance may grow over a meter and can weight a lot of kilos. In the countries of their origin they are food fish and they are “cultivated” for this purpose. In aquaria they usually do not grow more than 20 cm in length. They tend to stress a lot due to this barbarism and they become vulnerable to bacterial infections.

PIMELODIDAE – SILURIDAE - CLARIIDAE

Other species that may win the same title as above are species of these two families. With a maximum size of over one meter (Phractocephalus hemiliopterus, family PIMELODIDAE), imagine what these fishes are forced to tolerate. Another “fashion” during the last years is trading members of the SILURIDAE family. Species of the genus Acipencer, known as sturgeon fish are sold as fish for aquaria. These species not only suffer barbarism that the females endure when they are cut open while alive, so that their eggs can be collected for caviar and then sewn up with needles and thrown back in the water, but they are also forced to live as pets in unsuitable tanks (small with high temperatures) for a while as babies. These fish are distributed, illegally of course, as they are endangered species, and capture, export or import is prohibited by international laws. They are usually distributed from northeastern European countries and the species we find in pet shops is usually Acipenser ruthenus. The size of the fish can go up to 3,3 meters and their life span is about 100 years. Their weight can reach many tens of kilos.

In our country, there is an endemic (probably distinct subspecies) of the family SILURIDAE, Silurus aristoteles that lives in the rivers of Macedonia (not the Former Yugoslavian Republic Of Macedonia, which is the country of Scopje. They have been given (for unknown political reasons) the same name, as that of this historical Greek region (homeland of Alexander the Great) and Thrace territory on the north of the country. The big specimens of the CLARIIDAE family members obtain a small measure of revenge for these tortures, as they will devour all their tank mates that fit in their enormous mouths over by time, but they still live in misery within small tanks. Imagine that in their natural environments they live with crocs and hippos. Usually Clarias batrachus are kept in home aquaria.

SCHILBEIDAE - MALAPTERURIDAE – ASPERINIDAE – BAGRIDAE – CHACIDAE – ICTALURIDAE - TRICHOMYCTERIDAE

The species of the SCHILBEIDAE family are very interesting species. Many of them are endemic in Victoria, like Schilbe intermedius. They live both in Africa (Pareutropius buffei) and Asia. The smaller Asian species like Κryptopterus bicirrhis are a very interesting addition in community tanks, as long as they are kept in small schools with peaceful tank mates.

MALAPTERURIDAE, ASPERINIDAE, BAGRIDAE, CHACIDAE, ICTALURIDAE and TRICHOMYCTERIDAE are rather rare in the hobby, except for some species of Auchenoglanis as Auchenoglanis occidentalis (family BAGRIDAE). These are coming into the trade by accident with other wild caught species that are the target species for the collectors. They are hardly sold and they become large, so they are not species that we should keep in tanks, unless we have really large tanks and suitable tank mates for them. They are nocturnal predators and we can find them among other species in the tanks of wholesalers.

Catfishes are very useful addition in a community tank and a very good option for species tanks. Their peculiarity gives beauty to our hobby. Some species are better off not to be kept as pets if the available tanks are small, and the parameters and aquascape are not suitable for them. Most of them (for instance Heteropneustes fossilis) have neurotoxic venom on their dorsal and pectoral fins, so we have to be careful when handling them. If by accident we happen to be punctured by them, we have to submerge the punctured limb into very hot water (as hot as we can tolerate, for as long time we can tolerate the heat), because this venom is quite unstable in high temperatures. Next step is to remain calm and take one or two aspirins, and if we are allergic to animals’ venom reach, as soon as possible, a doctor for further care of our wound. Corydoras spp “offer” the lighter venom, while Auchenoglanis occidentalis “offer” the strongest (from personal taste).

References

►Aquarium Atlas – Hans Baensch, Volumes I,II,III

►Aqualog – CORYDORAS, All C numbers

►Aqualog – LORICARIIDAE, All L numbers 

►STERBA – Encyclopaedia of all fishes

► T.f.h. magazine – Several issues

For more information on catfishes you may also read the following articles in this site : "The Pleco connection", "Peaceful Catfish - A Myth" and "Catfishes and African Rift Lake Cichlids"