The Bronze Corydoras

The Bronze Corydoras (Corydoras aeneus)

Order Siluriformes, Family Callichthyidae

Common names
Bronze corydoras, Bronze catfish

Synonyms
Corydoras schultzei, Corydoras macrosteus, Corydoras venezuelanus, Callicthys aeneus, Hoplosternum aeneus, Hoplosoma aeneum

Description
The bronze corydoras is a cheerful and outgoing fish, a group of which will always be busy around the aquarium. The back and sides are a medium brown, sometimes appearing metallic. The stomach is paler. Males and females are very similar, although the females are larger and fatter – the difference is easiest to observe from the top. This is one of the most common species kept in aquaria; although there are a number of other Corydoras species that could be confused with aeneus by the beginner, these are usually labelled as something else in the shop or far more expensive. The bronze corydoras is one of the bigger species, reaching a length of about 3 inches.

Behaviour
All Corydoras are very social fish, and need a group of at least six to be happy and seen at their best. They will happily shoal with other Corydoras of a similar size, so in a community tank the shoal can be of mixed species. Bronze Corydoras are rarely shy, and will be seen out and about in the aquarium regularly, often swimming in midwater. They are capable of breathing air at the surface, and will often be seen darting up for a gulp of air even when the water is not oxygen-deficient. They tend to do this as a group, so as soon as one heads for the surface all the others do too.

Aquarium requirements
Their home aquarium needs to have enough space for a shoal of these active fish, and the substrate should have no sharp edges. Sand is best, although they can be kept on smooth rounded gravel. It is essential that the substrate is kept clean, as they spend a lot of time rooting through it, and their sensitive barbels may become infected and even disappear entirely in a dirty tank. Once the barbels are damaged they rarely regenerate. Corydoras aeneus are happy living and spawning in water between pH 6 and 8, although other Corydoras species may need soft acidic waters.

Feeding
Although Corydoras are natural acrobats and will often manage to grab food from the surface, their natural way of feeding is from the bottom, and they should be provided sinking foods. It is important to make sure they get enough to eat, and not to expect them to survive on bits of food that the other fish miss. They will eat sinking pellets, and particularly enjoy frozen live foods or sinking live foods such as bloodworm. Live foods are important to keep them in the peak of health and bring them into condition for spawning.


Breeding
Corydoras often spawn after a water change; it is thought that the influx of cooler water fools them into thinking that the rainy season has come, as in their native South American waters. When they are spawning, the observer will notice a great deal of increased activity in the tank, with the males following the females and nudging at them. Eventually the pair assume a ‘T’ position, with the female’s head near the males vent. The male discharges milt, which is swallowed by the female (at least in those species where experiments have been conducted) and eventually reaches the two or three eggs being held between her pelvic fins. Once the eggs are fertilised, she remain still for a few seconds, then starts to search for a place to deposit the sticky eggs. These may be stuck onto leaves of plants, the aquarium glass, rocks, and anywhere else available. The spawning may go on for some hours, until all the eggs have been deposited. If one pair begins spawning, this may stimulate others as well. The little fry can be fed on brine shrimp nauplii and proprietary fry foods, but will fall victim to other community tank inhabitants unless the eggs are removed and hatched outside the community tank.

Diseases and disorders
The hardy little Corydoras are prone to few ailments, other than infection of the barbels. In a clean tank with good maintenance they should thrive without problems.

Notes
Bronze Corydoras are appealing, cute and easy to keep; their ability to move their eyes has convinced many an aquarist that their fish has winked at them. Most community aquaria will be enhanced by a group of Corydoras.

This article has been provided by Kathy Jinkings and cannot be reproduced without her permission

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