THE CATFISH:
Cats are probably the most variable group of fish in the world.
They are found almost everywhere other fish are found, and they display many adaptations that are not found in almost any other species.
Some cats, such as some of the Mochoquídeo family, which are found throughout Africa except in the desert, sometimes swim upside down, certain Synodontis .
These Mochoquídeos are very popular with aquarists even though they reach a fairly large size, are completely smooth in the sense that they have no scales or body armor of any kind, and are generally very expensive since they are all imported from Africa.
For the aquarist, the most common cats are the South American lode and the Callichtídeos family, the mesh cats.
These are small fish that get their name from the two rows of bony plates that overlap like armor.
Most fish in this family have very robust spines on their dorsal, adipose, and pectoral fins.
The serration of the pectoral spines can be highly variable from one species to another, especially in the genus Corydoras , and the author considers this feature extremely useful for identification.
Most Callichtids require access to air to supplement their gills with an occasional sip of air, which is used and absorbed at the bottom of their digestive tract.
Corydoras and Dianema , as well as the other members of this family, often swim quickly to the surface of the water to get a breath of air.
Not all members of the family raise the same way.
Corydoras , which are exported from almost every South American country east of the Andes, follow a very complicated spawning ritual that has not yet been well understood.
Basically, what a pair or group of Corydoras does is come together in a kind of orgy, during which the males and females lick the male's anal opening.
Such a circumstance strongly suggests that the female receives sperm in her mouth since no other activity indicates any contact with the male.
As soon as the female has established contact with the anal opening of the male, she releases a few eggs which she retains between her ventral fins, which take on a concave shape that closely resembles human hands in a cupped position.
The female then swims around the tank with her eggs held between her ventral fins and looking for a suitable point to deposit them, most of the time, it takes place on the front glass of the aquarium, although she may also choose a heating tube or a robust blade.
It appears to lick the area where it seeks to lay its sticky eggs, at which point it is claimed that it has already spit out the sperm and simply presses the eggs into the proper position on it.
In fact, the eggs are randomly distributed in small groups throughout the aquarium.
The Callichthys and the Dianema act very differently.
They build a bubble nest under a driftwood or large leaf and lay eggs under the nest, with the male guarding the floating eggs.
Incubation ends after five days, after which the male should be removed and the fry left to grow on their own.
There are many other families of catfish that are interesting to aquarists.
The so-called suckers, from the Loricariidae family, are also of interest due to the algae-eating characteristics of the members of this family.
While the Callichtídeos were characterized by the two rows of bony plates located laterally along the flanks, this family has three or four rows, with some even having the ventral surface covered with this same protection.
Hypostomus (Plecostomus), Loricaria, Farlowella, Otocinclus, and Ancistrus are some of the Locarids that are imported orCallichthys , and no one engages in commercial spawning of any Loricariids.
In addition to the three families of catfish considered so far, the order Siluriformes also includes the families Doradidae, Ageneiosidae, Plotosidae, Ictaluridae, Chacidae, Trichomycteridae, Schilbeidae, Helogeneidae, and Malapteruridae, all of which together represent a relatively small number of species of interest to aquarists.
Other families, which include many more species of interest to the aquarium hobbyist, are the Siluridae , which includes the popular glass cat species Krytopterus, the Clarilidae, which includes the obnoxious walking catfish, batrachus, the Pimelodidae which includes the Pimelodus and Pimelodella as well such as the Sorubim and the Sorubimichthys and the Aspredinidae which include the banjo cats.
Catfish, as a rule, are very hardy and adaptable.
Most are nocturnal and do best in dim light.
