The Bronze Corydoras is one of the hardiest and most popular aquarium catfish, making it a perfect choice for beginners and community tanks.
Overview
Corydoras aeneus, commonly known as the Bronze Corydoras, is one of the most widespread and popular catfish in the aquarium hobby worldwide. This species belongs to the family Callichthyidae and inhabits shallow rivers and streams across South America — from Trinidad and Venezuela to the La Plata basin in Argentina. In the wild, Bronze Corydoras prefer slow-moving waters with sandy or muddy bottoms and abundant vegetation.
Adults reach a size of 5-7 cm, and their lifespan under proper care is 5-10 years. The body is covered with two rows of bony plates, and two pairs of sensitive barbels on the upper jaw help the fish forage through the substrate. The natural coloration is a greenish-bronze with a metallic sheen, but an albino form with a white-pink body and red eyes is widely available in the hobby. The Bronze Corydoras possesses the ability to breathe intestinally: from time to time, the fish rises to the water surface and gulps air, absorbing oxygen through the intestinal walls. This is perfectly normal behavior, but if the fish do it too frequently, it is worth checking the aeration level in the tank.
Tank Requirements
A group of Corydoras aeneus requires a tank with a minimum volume of 40 liters. Optimal water parameters are: temperature 22-26°C, pH 6.0-7.8, general hardness (GH) 2-12. Bronze Corydoras are quite undemanding regarding water parameters but do not tolerate high levels of nitrates and nitrites.
Special attention should be paid to the choice of substrate. Sand or fine rounded gravel is the best option, as corydoras actively dig through the substrate searching for food, and sharp-edged gravel can damage their sensitive barbels. The tank should be furnished with shelters made of driftwood, rocks, and dense vegetation, while leaving open areas at the bottom for feeding. Filtration should provide clean water but create only moderate current — too strong a flow is uncomfortable for these bottom dwellers.
Feeding and Diet
Corydoras aeneus is an omnivorous species with a preference for animal-based foods. The core diet should consist of high-quality sinking pellets and wafers designed for bottom-dwelling fish. To ensure balanced nutrition, supplement dry foods regularly with live or frozen options: bloodworms, tubifex, brine shrimp, and daphnia.
It is important to understand that corydoras are not "tank cleaners" in the full sense of the word. While they readily pick up leftover food from the substrate, relying on this as their primary food source is unacceptable. The fish need dedicated feeding with sinking foods that reach the bottom. It is best to feed once or twice daily in small portions, preferably in the evening when corydoras are most active in foraging.
Care and Maintenance
The Bronze Corydoras is one of the most undemanding aquarium fish species, making it an ideal choice for beginner aquarists. To maintain the health of the fish, weekly water changes of 20-30% are necessary, along with thorough gravel vacuuming, especially in feeding areas. Monitor water parameters regularly — ammonia and nitrite levels must remain at zero.
Despite their hardiness, corydoras are sensitive to salt in the water and certain medications containing copper. This factor should be taken into account when treating diseases in a community tank. Healthy fish are active during the daytime, constantly exploring the bottom in search of food and periodically rising to the surface for intestinal breathing.
Compatibility
Corydoras aeneus is an exceptionally peaceful species, perfectly suited for community aquariums. Bronze Corydoras must be kept in groups of at least 6 — in a school, the fish feel more confident and display more interesting natural behavior. Excellent tankmates include small characins such as neon tetras, black neon tetras, as well as other peaceful bottom-dwelling species. They get along well with related species such as Panda Corydoras and Sterbai Corydoras.
Avoid keeping them with large or aggressive fish, such as cichlids, which may harm the corydoras or compete for food. Territorial bottom-dwelling fish are also undesirable tankmates.
Breeding
Breeding Corydoras aeneus is not particularly difficult, and this species is often recommended for novice breeders. To stimulate spawning, simulate the rainy season: perform a large water change (up to 50%) with water 2-3°C cooler than usual. A drop in atmospheric pressure can also serve as a spawning trigger.
The breeding process involves the characteristic T-position typical of corydoras: the female presses her head against the male's abdomen, forming a "T" shape, and fertilization of the eggs occurs at this moment. The female then deposits small batches of adhesive eggs (usually 2-5 at a time) on the aquarium glass, plant leaves, and other smooth surfaces. The total number of eggs can reach 100-200 per spawning event.
After egg deposition, it is best to remove the adults to prevent them from eating the clutch. The eggs develop over 3-5 days at a temperature of approximately 24°C. To prevent fungal infection, methylene blue can be added to the water. The hatched fry should be fed infusoria, micro worms, and baby brine shrimp, gradually transitioning to larger foods as they grow.