Another family of fish from South America that caught my fancy were the Corydoras. These are freshwater catfish of the genus Corydoras in the family Callichthyidae. Their genus name is an apt description of their appearance (‘Cory’ from the Greek ‘Kory’ for helmet, and ‘Doras’, Greek for skin). The family name Callichthyidae is from the same language and means beautiful (Kallis) fish (Ichthyis). These armoured creatures are very popular among aquarists. Other genera in the family are Callichthyis, Dianema, Hoplosternum, Lepthloplosternum, Megalechis, Aspidoras and Scleromystax. Callichthyidae are part of the superfamily Loricarioidea along with the likes of Trichomycteridae (pencil catfishes) and Loricariidae (suckermouth catfishes).
The distribution is South American. They are small in size (with a few exceptions like Hoplosternum littorale). The body is covered by rows of overlapping bony plates. These, along with the bony scales of the head provide them defense. Found in a wide variety of habitats, the Callichthyids are capable of swallowing air to extract oxygen. This takes place inside their guts. Another unusual aspect is seen during mating. Females of some species of the genus Corydoras swallow the sperm released by males, letting them pass through their digestive tract. They are released into a pouch containing the female’s eggs (which when fertilized are deposited among the underwater vegetation).
Of all the genera, the Corydoras species are the smallest. They live in slow-moving, clear waters, usually on the river bed. Shoals of Corydoras forage on the bottom, using their barbels to find food. Many are camouflaged. The species that I procured for my aquarium was the Panda Corydora (Corydoras panda). It is so named because of the black spots surrounding its eyes, making it look a lot like its Chinese namesake. They are very small and reach a size of 2 inches at most. Despite a reputation for living as long as 10 to 15 years, the specimens I bought lasted only a year. Other species that have become popular in the aquarium trade are the Bronze Corydoras (Corydoras aeneus), Dwarf Corydoras (Corydoras hastatus) and Emerald Corydoras (Corydoras splendens).
Image Attribution: The image above is sourced from Wikimedia Commons and based on an illustration from the book ‘Expédition dans les parties centrales de l’Amérique du Sud, de Rio de Janeiro à Lima et de Lima au Para’, documenting the species discovered by an expedition under the command of the French naturalist, Francis de Laporte de Castelnau (1810-1880). The explorers charted the territory along the watershed between the Amazon and the La Plata systems, from Rio de Janeiro in the east to Lima in the west, before heading north to the state of Para on the Atlantic. The species portrayed is Atipa (Hoplosternum littorale). It is raised both for the aquarium trade and as a food fish.