Order Catfishes ( Siluriformes )
This order includes more than 1,600 species of fish, ranging in size from 1 cm to 5 m. Most representatives of the order inhabit tropical and subtropical regions of Asia, Africa, and America. There are no catfishes in the rivers of Australia and Madagascar. Most of them are freshwater fish. Catfishes are perhaps the most diverse group of fish in terms of size, body shape, lifestyle, and environmental requirements. Often, catfishes look unusual and even bizarre, although their coloration palette is not very rich.
Catfishes are generally devoid of scales and are covered either with thick skin containing a large amount of mucus, or with bony plates. The dorsal and pectoral fins of these fish are equipped with spines, which in many species can be fixed in a certain position. This provides a mass of advantages: stability increases when resting the pectoral fins on the bottom substrate, if necessary, using fixed spines, the fish can wedge itself into some crevice or cavity, and by defending itself against predators with the fin spine pointed forward, the fish becomes larger and less vulnerable. Fish whose bodies are covered with bony plates cannot swim for a long time because their movements are hindered.
Some catfishes breathe atmospheric air to a significant extent and may even suffocate without access to the water surface. However, when a water body dries up, these fish are able to crawl overland in search of a new habitat or bury themselves in the mud. Most catfishes spend the major part of their lives at the bottom. Some fish are schooling and need to be kept in groups.
They feed primarily on animal food. Almost all catfishes are predators that eat small fish and aquatic, mostly benthic animals; herbivorous forms are very few. All catfishes have barbels located near the mouth opening. Regardless of their shape, the barbels are an extremely sensitive organ of taste and are used to search for food.
Some species sift the substrate. If you have such fish, you need to carefully select gravel or sand, otherwise the fish may damage or cut their mouth-area structures. Usually, long barbels indicate that their owners can hunt smaller fish. The same is true for catfishes with large mouths.
Catfishes are a permanent fixture in almost any aquarium. They are added here at least to liven up the bottom zone. Some enthusiasts even want to see only catfishes in their aquarium and try to arrange the tank so that the maximum number of species finds shelter there. To liven up the middle layers, distichodonts, African tetras, and other agile neighbors of medium and large sizes are kept in the company of catfishes.
All catfishes, including the few that swim in the middle water layers, need shelters where they can hide or seclude themselves and rest. This can be easily arranged by placing driftwood, grapevine roots, rocks, and plenty of plants in the aquarium.
It is necessary to make sure that while moving the substrate, the catfishes do not undermine or topple heavy rocks or other objects. It is very important to study reference literature before acquiring catfishes, because these creatures probably more often than representatives of any other groups become victims of misconceptions about them.
Many fish enthusiasts believe that although catfishes are extremely diverse in appearance, their behavior and maintenance conditions are completely identical. Here are the most common mistakes often made by aquarists.
• Failing to realize that some catfishes grow very large. The length of these fish ranges from a few centimeters to two meters or more, while large individuals can live for many years. Such a large size range can be observed in some families. Thus, if representatives of a certain species are known to be small, this is by no means a guarantee that their close relatives will also be small.
Very often, small catfishes purchased grow within a few months and turn into all-destroying giants, bringing chaos to the aquarium design, eating less agile and large relatives, as well as other neighbors.
Aquarists should be especially careful when it comes to red-tail catfish Phractocephalus hemioliopterus. They are often sold as extremely attractive young fish 8-10 cm long, but then they very quickly grow into monsters more than a meter long, and ultimately become much larger.
• Many fish that are initially indifferent to vegetation, as they grow, begin to intensively nip young shoots and “perforate” old leaves.
• Most catfishes are nocturnal or crepuscular. During the day, they either rest somewhere in shelters, sluggishly moving from place to place, or openly sleep. Activity increases only in the evening hours. Forgetting that many catfishes are nocturnal fish and need to be fed shortly before the lights are turned off in the aquarium.
There is nothing you can do with typically nocturnal inhabitants, but crepuscular catfishes can be slightly “re-educated” by reasonable feeding restrictions. Once accustomed, such fish eventually become tame: like cichlids, they actively react to what is happening behind the glass, recognize their owner, do not refuse to interact, and take food from hands.
• Assuming that catfishes of all species will readily eat any food and feel fine feeding on leftovers. In fact, many catfishes require special food, and larger representatives of catfishes are often ferocious predators.
• Believing that all fish with sucker mouths feed on algae. But in reality, not all such fish are vegetarians, and a regular aquarium does not hold enough algae to feed even a single fish.
• Using large gravel as substrate for bottom fish, so that their delicate sensitive barbels and unprotected belly are injured, and infection penetrates through the wounds.
• Not knowing that some fish are schooling and need to be kept in groups.
• Assuming that catfishes of all species have a protective armor and are therefore invulnerable to other fish.
• Not knowing that some freshwater species of catfishes cannot tolerate salt in the water at all.
• Failing to take into account that the spines on the bony plates and fins of these fish can pierce not only natural enemies, but also plastic bags and even the hands of aquarists! Sometimes these spines are covered with poison, so any wound is extremely painful.
Suborder Siluroidei ( Siluroidei )
They inhabit almost any water body. Inhabitants of drying water bodies bury themselves in silt and can stay there for a long time waiting for water falling during the rainy season with tropical downpours. Some are able to make significant journeys over land in search of water bodies that have retained water. Catfishes from swampy water bodies have additional respiratory organs, with the help of which they absorb oxygen from the atmosphere. Catfishes that have settled in fast mountain rivers have developed adaptations (suckers) that allow them to hold on in the rushing water current.
A common characteristic feature of almost all catfishes is their benthic lifestyle. Some of them bury themselves in the substrate, others simply lie on the bottom, making minor movements associated mainly with searching for food, and only a few spend significant time in the water column, rushing to the bottom when danger appears. Most catfishes are predators feeding on fish and other aquatic animals.
Many use shelters as an ambush, where they lurk waiting for prey. Males are usually leaner than females and have additional features: enlarged fins, skin outgrowths, enlarged head, etc. Many catfishes guard their offspring. Aquariums keep very many species of small catfishes, usually no more than fifteen centimeters in length.
The diversity of catfishes is also manifested in their reproduction methods. Most catfishes care for their offspring in various forms. For example, females of the banjo catfish (Aspredo aspredo) carry their clutch on their belly. Armored catfishes of the genus Hoplosternum (Hoplosternum littorale) build a nest of foam, similar to labyrinth fishes. The Far Eastern catfish (Pelteobagrus fulvidraco) digs a burrow in the clay bank to lay eggs. At the same time, many dozens of fish often dig burrows side by side, resulting in the formation of peculiar colonies.
In the Lake Malawi catfish (Bagrus meridionalis), even more unusual features of parental care are observed. First, this catfish’s clutch contains, in addition to regular eggs, so-called trophic eggs — remaining unfertilized, they do not decompose, but are preserved and subsequently serve as food for the fry hatched from normal eggs.
The second feature of reproduction in the Lake Malawi catfish is that during the period of parental care, a small school of fry of this catfish often mixes with the fry of certain cichlids, in particular Copadichromis pleurostigmoides and Ctenopharynx pictus. As a result, such a mixed brood is guarded from predators by the joint efforts of fish of two different species.
Finally, among catfishes, there is a species that is a complete analogue of the cuckoo in terms of reproduction type, meaning it drops its fertilized eggs into the fish of another species, which not only guards the clutch but also incubates it in its mouth! This is the cuckoo squeaker (Synodontis multipunctata) living in East Africa’s Lake Tanganyika. And the foster parents of its fry are fish from the cichlid family, for example, the frontosa cichlid (Cyphotilapia frontosa). During spawning, tilapias first lay eggs on the substrate, fertilize them, and only then take them into their mouth for incubation.
During the brief period when the eggs have already been laid but not yet hidden in the mouth, a pair of Synodontis manages to spawn in the same place. As a result, when cichlids collect their eggs, the parasite’s eggs also get into their mouth. Just like real cuckoos, the Synodontis fry hatch earlier than the fry of the host species. The larvae and then the fry grow rapidly, develop, and begin to devour the host’s eggs right inside its mouth. As a result, usually only individual cichlid eggs manage to survive.
Aquariums with a large bottom area are preferable. Among plants, the most suitable are Cryptocoryne and Echinodorus species, which have a well-developed root system. Catfishes do not need bright lighting, so you should either make it dim or place a sufficient number of shelters in the aquarium. Otherwise, be prepared that your pets will not come out to “stroll” during the day anytime soon.
The basis of the decor of a catfish tank is driftwood and rocks. Driftwood is not only an ideal shelter for some catfishes, but also serves as a source of edible cellulose for them. It is very desirable that they abound in various kinds of hollows. Aeration, filtration, and water changes.
Catfishes are omnivorous. Aquarists often consider small catfishes to be scavengers and do not provide any appropriate food. The main diet of catfishes consists of regular foods: bloodworms, corethra, washed tubifex, pieces of fish, lean meat, black bread, zooplankton organisms (Cyclops, Daphnia), and quality dry foods.
Catfishes need to be supplemented with tableted spirulina for herbivorous fish (any catfishes, unless they are pronounced predators, gladly eat plant-based products). Catfishes mature at 1-3 years of age. They live in the aquarium from 5 to 25 years. dH 6-12°, pH 6.8-7.5, T 20-27°C.
Bagrichthys macracanthus, Hemibagrus nemurus, wyckii, wyckioides.
