Bronze Cory (Corydoras aeneus)

Common Name:

Bronze Cory.

Scientific Name:

Corydoras aeneus.

Family:

Callichthyidae.

Sub-Family:

Corydoradinae.

Distribution:

Trinidad and the Guianan plateau of South America.

Size:

Upto 3 inches or 7.5cm.

Diet:

In the wild, they eat some algae and lower plants as well as insects, crustaceans and worms. They can take flakes and pellets in captivity, especially those that are earmarked for Cories. Shrimp pellets are also greedily attacked. They will take Tubifex and bloodworms greedily, whether they are alive or commercially prepared.

Water Temperature:

They do best in temperatures between 72 and 82 degrees Fahrenheit.

Water Chemistry:

They live in water that is slightly acidic (pH 6-7, although 5.8-7.8 is cited as a range of possible pHs in which they may live). The water has a dH between 2 and 30, but soft water is better.

pH:

Ideally 6.5-7.5 (They prefer slightly acidic to Neutral water). Like many fish which are tank bred, they can be acclimatized to a ph slightly outside this range if carried out slowly and carefully.

Life Span:

8-10 years.

Housing:

10 gallons for a small shoal.

Sexing:

Females are larger and more robust than their male counterparts.

Breeding:

A lowering of temperature and barometric pressure, when done in conjunction with water changes, may very well induce spawning. Another trick is the feeding of live foods, especially Tubifex and finely-chopped earthworms. Two or three males to one female seems to be the optimal rate for successful spawning.
Males will pursue the females until they show interest. The female will then clean surfaces (mostly plant surfaces and the glass sides of the tank). There is then more courtship -- the male rubs against the female and touches her head with his barbels. Finally, they start the classic "T-position" during vibrations which dislodge some eggs into the basket which the female has made with her ventral fins. They are then fertilized and the female places them throughout the aquarium. There is a quick rest and then the males advance on the females once again. This continues for a few hours (two to three, usually) and the female deposits up to 200 eggs.
The parents do not disturb the eggs or fry if well-fed, but they might be removed after the spawning so that the fry can be reared separately from their parents. The eggs darken over their five to six day incubatory period. Finally the wrigglers emerge and feed on infusoria for a little while. Supplemental feedings may start within the first week and advancement to fry foods for egg-layers should occur at the end of their first week.

Description:

These tiny little catfish can attain lengths of 3" at a maximum. The wild type is a muted coppery bronze. They are, and have the appearance of being heavily armored. They are among the "scaleless fishes", so this needs to be considered when adding medication to the tank. They are also able to utilize atmospheric oxygen with their intestines (but this does not mean that water changes may be ignored). The most prominent features of this species, however, are both their barbels and the eyes, which can sometimes be observed in a motion somewhat like a wink.

Behaviour:

These are peaceful shoaling fish. While they have been implicated in the deaths of tankmates, it has been said that if a Cory is seen snacking on a tankmate, one can rest assured that the Cories did not kill it.
They need a shoal of 4+ Corydoradines in order to feel comfortable in their surroundings and in order for you to see the range of corydoradine interactions.
One note that is of the utmost importance: Cories sense food by smell more often than by sight. This is important for two reasons; one, they need to have the barbels remain relatively intact as these are their olfactory sensors. And, secondly, a Cory that will not eat when it is immediately chow time may not know that such is the case. I have seen many a time when a Cory can have pellets dropped almost literally on top of them and not find it until ten minutes later after taking a circuitous route reminiscent of the most convoluted Bil Keane comic.
Cories will dash to the top to take gulps of air, though they should not be doing this on a frequent basis. One of the first signs that a water change is overdue is the Cories taking disproportionate top runs.
They will also feed at the top if they discover that their tankmates do that and pick up on cues that this is the day's method of feeding.
Cories have the ability to segregate themselves into conspecific groups even though humans may not be able to tell them apart.

Tank levels:

Most of the Cory's are bottom feeders, they scavenge the gravel looking for food particles.

Ease of keeping:

Excellent beginners fish, fun and colourful, makes an excellent addition to any planted peaceful aquarium.

Miscellaneous:

Albino C. aeneuses are so common in the hobby that it has become hard to find the wild-type. If you have an albino cory, you can be almost certain that it is C. aeneus or C. paleatus. If it is not seemingly elongated, you have an albino C. aeneus.
There are a lot of varieties of C. aeneus being discovered in the wild, but these "[color]-striped" varieties are likely to receive specific status in the next few years once they are further studied. The C. aeneus var. 'Black' is probably going to remain a color morph of C. aeneus.
Almost every pet shop in America has the albino C. aeneus and these cute little fish with reddish eyes make beautiful additions to a tank with darker-colored gravel if you like a huge coloric contrast or muted gravel if the contrast should be more subtle.
I personally have one albino (remainder of a pair) that lives with a C. julii and a C. ambiacus in their own 10 gallon tank. These three have thrived on a diet of Tetra sinking pellets, Wardley's shrimp pellets, and the occasional Spirulina flakes. It is truly easier to have success with cories if they are not treated as scavengers but as community inhabitants of their own right.

Photo Credit:

Photos supplied courtesy and ^©Bob Hart (Rab).