About the Blackfin Cory
Species Type: Freshwater Fish
Care Level: Easy. Does well in a slightly more narrow range of water parameters and shouldn't be used to cycle an aquarium. Will eat most prepared foods. May have some specific care requirements in terms of particular water parameters, social behaviors, food items etc.
Origin: Upper Amazon River basin in Colombia, Peru, Ecuador and into Brazil. Wide-spread in mainly-blackwater main river channels and tributaries. Always found in very large groups.
Compatibility/Temperament: Peaceful. Absolutely must be in a group, minimum five if alone (sole species) but in mixed species at least three. Very social, and always found in groups of hundreds in its habitat.
One of several cory species sharing a spotted patterning. Collections often include the very closely-patterned sympatric species Corydoras agassizii, C. ambiacus and C. gomezi. The present species can be identified by the vertical dark eye band (the "mask"), and the black blotch in the dorsal extends onto the body of the fish, with a clear outer edge to the actual fin. C. gomezi has a distinct black dorsal spot and C. agassizii has less black in this fin, and both C. ambiacus and C. agassizii lack the distinct ''mask."
Although a stricter habitat aquascape would involve a muddy substrate, no plants, and chunks of bogwood, a more preferable aquarium would include a smooth fine gravel or (preferably) sand substrate, chunks of wood, and live plants. Provide some open areas, and subdued lighting which may be partly achieved with floating plants; most cory species do not appreciate bright lighting. The aquarium may be quite heavily planted; this species--like the "dwarf" species C. pygmaeus and C. hastatus--spends the majority of its time swimming in the water column off the substrate, browsing every plant leaf right up to the surface.
This is one of the few species of cory that manages at higher temperatures, as noted under the Ideal Water Parameters data.
There are no external gender differences; females are rounder when viewed from above.
As noted under Origin, this species is found in very large numbers. Available fish will be wild caught, mainly from Peru or Colombia, and may arrive mixed in with some of the sympatric species described above. Planet Catfish reports that among collectors in Amazonia this species is known as "Maldito," meaning the little damned cory, because it is so common and thus brings a very low price.
The Corydoras are quite sensitive to water parameters and quality, and highly intolerant of salt, chemicals and medications. Signs of stress usually begin with rapid respiration, then lethargy (often just "sitting" on plant leaves, wood or the substrate respirating heavily, sometimes near the surface) and sometimes rolling onto one side. At such signs, a partial water change of at least 50% with a good water conditioner should immediately be made, and appropriate steps taken to remove the cause. Any sudden fluctuation in water chemistry or temperature often induces shock, causing the fish to "faint" and fall over on its side. Corydoras introduced to new aquaria will settle in better if the tank is established; Corys do not adjust well to a new aquarium with still-unstable water conditions and fluctuations.
The dorsal, pectoral and adipose fins are each preceded by a spine which is actually a hardened and modified ray; the pectoral fin spine can be "locked" into position by the fish; care must be taken when netting Corys not to entangle these spines, which can also give the aquarist a nasty jab. They are believed to be a defense adaptation, to lodge the fish in the throat of a predator.
All species in the genus will periodically and fairly regularly swim quickly to the surface for a gulp of air. The fish swallows the air and blood vessels in the hind gut extract oxygen from the air; it is then expelled through the vent the next time the fish breaks the surface for another gulp of air. This adaptation is believed to have evolved so that the fish can survive in poorly-oxygenated water such as drying pools during the dry season. It is however essential to the fish's well-being that it regularly swallows air.
The genus name is derived from the Greek "cory" meaning helmet, and "doras" meaning skin, incorrectly used here for "armour"; it refers to the dual row of overlapping plates (instead of scales) along the body, comparable to a suit of armour.
The species was described in 1942 by C.H. Eigenmann and W.R. Allen, using the type specimens collected in Yarinacocha, a cutoff lake on the right bank of the Rio Pacaya, near Sarayacu, Peru. The species epithet means with white and black, a reference to the pattern. The species described by H.W. Fowler in 1943 as Corydoras caquetae was deemed a conspecific by Nijssen & Isbrucker (1980) and the name is thus invalid as a distinct species.
Blackfin Cory Diet
Naturally feeds on crustaceans, small worms, insect larvae. Readily accepts prepared foods that sink such as tablet and pellet; frozen bloodworms and live worms are relished as treats.
Maximum 2.2 inches (55 mm).
Minimum Tank Suggestion
Ideal water parameters for Blackfin Cory
Soft to medium hard (< 12 dGH), acidic (pH < 7), temperature 25-30C/77-86F.