Corydoras aeneus (Bronze corydoras)

Corydoras aeneus which is most known as the bronze corydoras belongs to the Corydoradinae subfamily, Callichthyidae family, and Siluriformes order. Another common name of the species is the green corydoras.
The species is native to South America (Venezuela, Trinidad, and Argentina). In general, Bronze corydoras occur mostly in shallow, clean or muddy pools, in margins of ponds and streams covered with plants, stagnant waters with soft bottoms (sand) but also inhabits slightly running waters. The water has a high amount of tannin due to the decomposition of leaves and wood that makes the water tea-colored (an indication of soft and acidic habitat). Furthermore, Corydoras aeneus occur in seasonally flooded rainforests. In that case, a large number of the corydoras, as well as other animals that left behind in this low oxygen habitat are bound to die as the water gets drier and more polluted.
Corydoras aeneus have a short and rounded snout with six barbels around the mouth that are used as tactile organs to obtain physical information about objects, to find food and in courtship. The color of their body is pink and brown with an iridescent greenish color over the head and the side. There is also an albino variation.
Corydoras aeneus as other corydoras species has tubular, axillary glands near the first pectoral ray filled with a homogenous secretory product. In general, many catfish with poisonous spines use their spines as a defense mechanism for predators. However, Corydoras species are not considered toxic catfishes like other catfishes and the exact purpose of the axillary gland discharge is still unknown as well as the contribution for the pain that people suffer when stung by the pectoral fin ray. The secretion discharged by the corydoras presumably during stress.
Even though Corydoras breath with their gills, they also breathe air from the surface intestinally. The surface air gets stored by the corydoras in the thin walls of intestine’s posterior part. As a result of the modification and vascularization of the posterior intestine, makes the organ well suited for gas exchange.
(Immunohistochemical and ultrastructural evidence of functional organization along the Corydoras paleatus intestine)
The species have an average size of 2.7 inches (7 cm) with females being insignificantly bigger than males and with a larger abdominal region. The species have a lifespan of 5 years, but with the right conditions they may live up to 7 years.
(Axillary glands in the armored catfish Corydoras
That nocturnal catfish is an excellent choice for beginners because of its hardiness, active but peaceful temperament. It’s advised to keep the species at least in a group of 5 corydoras and more due to their schooling behavior. In nature, the species usually live in shoals of 20-30. Because of their peaceful temperament corydoras are compatible in community tanks with many species (peaceful) such as tetras.
Because of the natural habitat of Corydoras aeneus should be kept in soft acidic water. Although the species can survive in a wide range of water parameters(6-8 pH, 20-28 Celsius), a pH between 6.5-7.0, with a temperature between 22-26 Celsius, and a hardness between 50-150 mg/l, suits the species.
An aquarium with 51 liters of water(13,5 gallons) is suitable for a shoal of 5-6 bronze Corydoras. Although plants are not usually a characteristic of corydoras aeneus‘ habitat, a planted aquarium has many advantages for the owner and the fishes. The substrate must be soft and the decoration without sharp points for the avoidance of injuries of the corydoras’ sensitive barbels.
Many beginners use the species to clean the bottom from the leftovers of other fish in the aquarium but like all animals need a proper diet. Some even think that corydoras are coprophagous which is a myth. Corydoras aeneus are omnivorous and can eat prepared food (sinking pellets) and small live-foods such as brine shrimp, bloodworms, daphnia, etc. In nature, their diet consists of worms, crustaceans, and plant matter.
Corydoras aeneus are easy to breed in the right conditions. In their natural habitat reproduction occurs in the rainy season (change of chemical and physical quality of water). In the aquarium, you can trigger breeding by changing a large amount of water (20-50%) or daily water changes (10%) and lower the temperature a bit (2-4 Celsius). One way to reduce the heat is by cooling water changes. Another way to reduce the heat is with a heater. I have to mention that Lowering the temperature in community tanks can cause negative consequences on other species. Furthermore, the addition of a varied diet of high quality aids the reproduction of the species, as well as raising the amount of the food than the usual portion.
During breeding conditions, they chase each other around the tank with the male displaying his abdomen for the female. Then the female corydoras’ mouth will adjust over the male’s opening to collect the sperm, forming the characteristic T-position. The sperm travels to the eggs through the female’s intestines. After the fertilization of the eggs, the female releases and deposits the eggs in a safe location (rocks, glass, leaves of plants). The action is repeated many times by the corydoras.
Corydoras produce about 200 eggs in one day. The young hatch after 3-5 days with a temperature of about 22 Celsius (the hatching period of the young is affected by the water’s heat) and for 2-3 days feed on the yolk sac, so in that period they don’t need food. After the consumption of the yolk sac, they search for food on the bottom. You can feed the young three times per day with brine shrimp, micro-worms, powder food, etc.
For the survival of the young, the species is best to spawn in a breeding tank with shallow water. When the whole process ends, remove all the adult corydoras. You can also place the offspring in breeding traps or plastic containers. Furthermore, the addition of an air pump helps the flow of water and prevents the infection of eggs from fungus. You can also use fungicides for a better outcome.

The Bronze Corydoras (Corydoras aeneus) a popular freshwater aquarium fish.


  1. Richard Geis 1999, Catfish keeping and breeding in captivity, Chelsea House Publishers, ISBN10 0791050890
  2. David Alderton 2005, 2008, Encyclopedia of aquarium and pond fish, Published in the United States by DK Publishing, ISBN 978-0-7566-3678-4
  3. UWI, Corydoras aeneus. Retrieved from
  4. Immunohistochemical and ultrastructural evidence of functional organization along the Corydoras paleatus intestine 2016. Retrieved from
  5. U.S. Fish & Wildlife Service 2013, Bronze Corydoras. Retrieved from
  6. Hartmut Greven1, Tim Flasbeck2, and Dieter Passia, Axillary glands in the armoured catfish Corydoras aeneus. Retrieved from
  7. Corydoras Aeneus. Retrieved from
  8. Corydoras Aeneus. Retrieved from

How useful was this post?

Click on a star to rate it!

Average rating / 5. Vote count:

Leave a Reply

Your email address will not be published. Required fields are marked *