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Bronze Cory

Scientific Name: Corydoras aeneus
Family: Callichthyidae, Subfamily Corydoradinae

About the Bronze Cory

Species Type: Freshwater Fish
Category: Catfish

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: Widely distributed on the eastern side of the Andes range in South America, with records from every country except Chile; it is also native on Trinidad. Occurs along the banks of slow-flowing rivers and streams having a substrate usually of sand, sometimes mud.

Compatibility/Temperament: Peaceful, must be in a group of five or more; if several cory species are combined, a minimum of 3 per species is suggested. Avoid keeping corys with fish that would regard them as food.

Description

This is one of the hardier of the cory species, and was one of the first kept by aquarists and bred in captivity. An albino form was developed. Available fish will almost certainly be commercially raised.

Spawning is relatively easy. Females are slightly larger and as they mature rounder than males when viewed from above, but otherwise there are no external differences. Lifespan is usually stated to be 5-10 years, with reports of fish surviving up to 20 years.

Set up: Corydoras prefer sand or fine gravel without any sharp edges. As their barbels are sifting through the substrate continuously looking for food it is essential when housing Cory's that the substrate is cleaned each week with a vacuum; it is suggested by many reputable authors that Cory's housed on substrate that is not regularly maintained it can cause barbel infections. They appreciate cover within the tank; that can be larger plants or caves or large pieces of driftwood to hide in/under during the day.

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; Cory's 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.

Considering the wide distribution of this species, it is not surprising that there are a number of colour forms being discovered in South America. The green and gold forms appear to be wild. There is also a black form with reddish fins that appears to be man-made. Some of these were described as new species [see further below].

The gold stripe, red stripe, and green laser stripe variants may be seen periodically; these forms will be wild caught, and attention should be paid to the habitat water parameters. When initially discovered, they were considered to be variants of the subject species, but several have been given "C" numbers pending further scientific study.

Photo examples of these variants are shown on Planet Catfish. Sadly, this species has also been subjected to the cruel practice of dye injections to obtain outlandish varieites; these should never be purchased.

The species was originally described by T.N.Gill in 1858 and named Hoplosoma aeneum. Nijssen & Isbrucker (1980) moved it into Corydoras, and the species epithet changed gender to agree with the genus. 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. This species epithet is from the Latin meaning brazen, of copper. Four species, C. macrosteus, C. microps, C. schultzei and C. venezuelanus, were described during the first part of the 20th century but Nijssen & Isbrucker (1980) established these as conspecifics and the names are no longer valid as distinct species.

References:

Nijssen, H. and I.J.H. Isbrucker (1980), "A review of the genus Corydoras Lacepede, 1803 (Pisces, Siluriformes, Callichthyidae)," Bijdragen tot de Dierkunde, volume 50 (no. 1), pp. 190-220.

Planet Catfish link to the variant photos: http://www.planetcatfish.com/cotm/cotm.php?article_id=110

Bronze Cory Diet

In their habitat they feed on worms, aquatic insects and larvae, crustaceans. Readily accepts prepared foods and should be fed a varied diet on sinking foods. Frozen or live brine shrimp, bloodworms; vegetables such as lettuce, peas, cucumber, zucchini, yams.

Size

2.5-3 inches/~7.5 cm.

Minimum Tank Suggestion

24 inches in length, such as a 15g or 20g.

Ideal water parameters for Bronze Cory

Soft to medium hard (< 20 dGH), slightly acidic to slightly basic (pH 6 to 7.5), temperature 21-27C/70-80F, optimum around 24C/75F.

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