Catfishes: A Chaotic Biodiversity that is still Waiting to be Discovered - Page 3: Catfish families

Catfishes: A Chaotic Biodiversity that is still Waiting to be Discovered - Page 3: Catfish families

Written by Andreas Iliopoulos Thursday, 07 February 2002 00:00

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Catfishes: A Chaotic Biodiversity that is still Waiting to be Discovered
Page 2: Families
Page 3: Catfish families
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Doradinae

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

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 Cheiloglaninae and Mochocinae. Within Cheiloglaninae 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. multipunctatus, 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

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 Claridae 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

 

 

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