Callichthyidae, Subfamily Corydoradinae Common Name: Origin and Habitat:
Rio Poranga, a stream that joins a small tributary of the upper Rio Negro, Brazil. The stream is fast-flowing with a buff sand substrate. Compatibility/Temperament:
Peaceful, typical cory species that should be kept in a group of at least five of its own species, though three or four will suffice if there are other cory species in the same tank. Perfect for a community aquarium of non-aggressive fish with similar water requirements. Cory Diet
Feeds on worms and insect larvae in its habit; will readily accept prepared sinking foods like tablets and pellets, and frozen bloodworms and live worms will be relished as treats. Size
May reach 2.5 inches but generally around 2 inches. Minimum Tank Suggestion
24 inches in length. Water parameters for Cory
Soft (hardness below 10 dGH) acidic (pH below 7.0) water, temperature 20-26C/68-79F. Tank-raised fish may adapt to slightly basic water, pH up to 7.4 and moderate hardness to 20 dGH. The habitat creek water is soft and slightly acidic. Description
This species is often seen in stores under the name Adolfo's Cory, which technically belongs to Corydoras adolfoi
, a remarkably similarly-patterned cory. C. adolfoi
was the first of several species that share this similar colour pattern to be discovered [see below], and the common name "adolfo" has been used interchangeably. The true C. duplicareus
is now more often seen in the hobby, having become popular due to its more intense colouration and pattern; the orange post-orbital fleck is significantly more intense in this species (not fading with age as occurs in C. adolfoi
), and the black upper dorsolateral band and black eye band are much broader. C. duplicareus
was discovered in 1994 by David Sands who subsequently described and named the species in 1995. The species epithet is the Latin "to duplicate," a reference to the earlier fish C. adolfoi
. A sympatric species having an identical colour pattern but with a longer snout was also discovered at the same time by Dr. Sands, and described and named by him as C. serratus
, a reference to the highly-serrated pectoral spine compared with that of C. duplicareus
that is moderately serrated.
Some 12 new species were discovered during the two decades from 1980 to 2000, each endemic to specific southerly-flowing tributaries of the upper Rio Negro, and having very similar cryptic (camouflaging) colour patterns. When viewed from above in the habitat, the colour pattern of all these fish cause them to blend in with the twigs and branches that litter the buff-coloured sandy streambeds. The patterns include a buff-coloured body with a black dorsolateral band (that may only be partial on some species), a black eye band, and an orange post orbital fleck in the shape of a "V" when viewed from above, the intensity of which varies between the species.
A well-planted tank containing some pieces of bogwood and some open substrate (small gravel or sand, provided it is smooth-edged) will suit this fish. This species appreciates a gentle flow from the filter to replicate its habitat [see comment under Origin]. As with all corys, mature females are rounder when viewed from above.
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 Cory's 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 name of the genus, which was erected by B.G.E. Lacepede in 1803, is derived from the Greek cory
[= helmet] and doras
[= 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. References:
Sands, David D. (1995), "Four new Corydoras
(Callichthyidae) species from Upper Rio Negro tributaries and a range extension, together with a discussion of C. bicolor
Nijssen & Isbrucker," Freshwater and Marine Aquarium Magazine
, Volume 18, No. 7 (June 1995), pp. 8-18. Contributing Members
The following members have contributed to this profile: Byron