The Bronze Corydoras (Corydoras aeneus) is one of the most popular freshwater fish for community aquariums. Also known as the Bronze Catfish, this species is peaceful, hardy, and easy to care for. They are part of the Corydoras genus, which includes over 160 species of small, bottom-dwelling catfish native to South America.
Bronze Corys are scavengers, helping to clean up leftover food at the bottom of the tank. However, they still need proper feeding to ensure they get enough nutrition. They have bony armor plates for protection and sensitive barbels (whisker-like feelers) to help them find food in the substrate.
Size and Life Expectancy
Bronze Corydoras typically grow to 2.5 to 3 inches (6-7.5 cm) in length. They have a lifespan of 3 to 4 years, though they can live longer with excellent care.
Varieties
While the classic Bronze Corydoras is the most common, there are also:
- Albino Corydoras aeneus – A white or pinkish version with red eyes
- Longfin Corydoras aeneus – A variety with longer, flowing fins
Range and Habitat
Bronze Corydoras are native to South America, including countries like Colombia and Trinidad. In the wild, they live in slow-moving rivers, streams, and floodplains with soft, sandy bottoms. They are social fish that thrive in large schools of at least 20 to 30 individuals, so keeping them in groups of at least six in captivity is highly recommended.
Caring for Bronze Corydoras
Tank Size and Substrate
For a group of 6+ Bronze Corydoras, a 20-gallon tank or larger is ideal. They are bottom dwellers, so the substrate plays an important role in their health. Soft sand or smooth gravel is best to prevent damage to their barbels. Sharp or rough substrates can cause barbel erosion and infections.
Temperature and Water Conditions
Bronze Corys thrive in water temperatures between 22°C – 26°C. They can tolerate a pH range of 6.0 to 8.0, but a slightly acidic to neutral pH (6.5 – 7.8) is ideal. Water hardness should be between 5° to 20° dH.
Filtration
A gentle but efficient filter is necessary for keeping the water clean. Since Corydoras are bottom-dwellers, strong currents from filters can stress them out. A sponge filter or a low-flow hang-on-back filter works well for their needs.
Cleaning and Maintenance
Regular maintenance keeps your Corydoras healthy:
Perform weekly water changes of 20-30% to keep the water parameters stable. Regularly vacuum the substrate to remove waste, but be gentle to avoid disturbing your Corydoras’ environment.
Feeding
Bronze Corydoras are omnivores that primarily feed on small insects, worms, crustaceans, and plant matter in the wild. In captivity, they need a balanced diet of high-quality sinking pellets supplemented with frozen or live bloodworms, blackworms.
Even though they scavenge leftover food, they should be target-fed to ensure they get enough to eat, especially when housed with faster, more aggressive eaters.
Best Foods:
- Sinking pellets
- Live or frozen bloodworms, blackworms, and daphnia
- Algae wafers and shrimp pellets
Corydoras with Plants
Corydoras do well in planted tanks. Live plants like Java Moss, Anubias, and Amazon Swords provide shade and security while improving water quality and reducing stress.
Some great plants to help Cory Catfish feel secure include:
- Java Fern
- Anubias
- Amazon Sword
- Java Moss
- Water Wisteria
- Hornwort
- Vallisneria
- Dwarf Sagittaria
Health and Diseases
Common health issues include barbel erosion (due to poor substrate or water quality), bacterial infections, and parasitic diseases like Ich. Keeping the water clean and stable is the best way to prevent illness.
Tank Mates
Bronze Corydoras are peaceful and social, making them great for community tanks. Good tank mates include:
- Tetras (Neon, Cardinal, Ember)
- Rasboras
- Guppies and Mollies
- Dwarf Cichlids (like Apistogramma)
- Other peaceful bottom dwellers like Kuhli Loaches
- Snails (such as Ramshorn Snails or Apple Snails
Avoid aggressive or large fish like Oscars or big cichlids that may eat them.
Hiding Places and Decor
Corydoras feel safest when they have plenty of hiding spots. Adding caves, driftwood, and rock formations can make them more comfortable.
CJAquatic’s custom aquarium accessories offer perfect hiding spots for Corydoras, helping them feel safe while enhancing the look of your tank.
Aquarium 250mm Under Gravel Cave Fish Hide Tank Decoration, Pleco, Loach, Corydoras Catfish Hideout
£10.99
Aquarium 200mm Under Gravel Cave Fish Hide Tank Decoration, Pleco, Loach, Corydoras Catfish Hideout
£9.99
Common Problems
Why is my Corydoras hiding all the time?
They might feel unsafe or stressed. Try adding more Corydoras to form a proper school or providing more hiding spots.
Why are my Corydoras not eating?
They might be getting outcompeted by other fish. Try feeding sinking pellets or feeding at night when other fish are less active.
Breeding
Breeding Bronze Corydoras can be a rewarding experience, especially since they are relatively easy to breed in home aquariums. This guide will cover everything you need to know to successfully breed and raise healthy fry.
Preparing for Breeding
1. Choosing Healthy Breeding Stock
Select a group of at least 6-8 healthy Bronze Corydoras to allow them to pair naturally. Males are typically smaller and slimmer, while females are larger with a rounder belly. Ensuring genetic diversity in your breeding stock will help maintain strong, healthy offspring.
2. Setting Up a Breeding Tank
A separate breeding tank is ideal to maximize survival rates. Here’s what you need:
- Tank Size: 10-20 gallons (larger if breeding multiple pairs)
- Substrate: Fine sand or bare bottom for easy cleaning
- Water Conditions: pH 6.5-7.5, temperature 24-26°C
- Filtration: Sponge filter for gentle water flow
- Lighting: Dim or moderate
- Hiding Spots: Add live plants (Java Moss, Anubias), caves, or hides.
1. Conditioning the Breeders
To encourage breeding, feed the Corydoras a high-protein diet for 1-2 weeks:
- Live or frozen foods like bloodworms, blackworms, and daphnia
- High-quality sinking pellets
Frequent small feedings (2-3 times daily) help females develop eggs more quickly.
2. Triggering Spawning
Bronze Corydoras often spawn after a temperature drop that mimics rainy seasons in their natural habitat. To simulate this:
- Perform a 25-50% water change using slightly cooler water
- Increase aeration to mimic increased oxygen levels during rain
- Repeat this process every other day until spawning occurs
Males will become more active, chasing the females in preparation for spawning.
Egg Laying and Fertilization
1. The T-Position Mating Ritual
Bronze Corydoras use a unique “T-position” during mating:
- The male positions himself perpendicular to the female’s head
- The female takes sperm into her mouth, which she uses to fertilize her eggs
- She then deposits the fertilized eggs on smooth surfaces
2. Egg Laying Sites
Females will attach eggs to surfaces like:
- Tank glass
- Leaves of broad-leaf plants
- Aquarium decorations
- Spawning mops
Each female can lay 50-300 eggs in small clusters.
Caring for the Eggs
1. Protecting the Eggs
Adults may eat their own eggs, so consider moving them to a separate hatching tank. Alternatively, remove the eggs gently using a razor blade or fingers and place them in a container with tank water.
2. Preventing Fungus Growth
To reduce fungal infections:
- Use an air stone to maintain water flow
- Add methylene blue or Indian almond leaves
- Remove any white, unfertilized eggs
Eggs usually hatch within 3-5 days.
Raising the Fry
1. Hatching and Early Care
- Fry will remain in their egg sacs for 24-48 hours before becoming free-swimming.
- Keep the water clean with gentle sponge filtration.
- Maintain stable water parameters with small, frequent water changes.
2. Feeding the Fry
For the first few days, fry will feed on their yolk sacs. Once they are free-swimming, start feeding:
- Day 1-7: Infusoria, liquid fry food, or powdered fish food
- Week 2-4: Baby brine shrimp, micro worms, crushed flakes
- Week 5+: Gradually introduce larger foods like crushed pellets
Feed small amounts multiple times a day to ensure proper growth.
3. Growth and Development
Bronze Cory fry grow quickly under optimal conditions:
- Week 1: Fry develop stronger swimming abilities
- Week 2-3: Start developing color and whiskers (barbels)
- Week 4-6: Resemble miniature versions of adults
By 8-10 weeks, they should be large enough to join a community tank.
Common Breeding Problems
1. No Spawning Activity
- Increase protein-rich foods
- Adjust water temperature drops during water changes
- Try different spawning triggers (cool water, increased aeration)
2. Fungus on Eggs
- Remove dead (white) eggs promptly
- Use antifungal agents like methylene blue
- Improve aeration to prevent stagnant water
3. Fry Not Growing Properly
- Increase feeding frequency
- Ensure proper food size and variety
- Conduct regular small water changes
FAQs About Corydoras
How many Corydoras should be kept together?
At least six or more to keep them happy and stress-free.
Do Bronze Corydoras clean the tank?
They help eat leftover food but do not replace regular tank maintenance.
Can Corydoras live with bettas?
Yes, as long as the betta is not aggressive.
Why do my Corydoras dart to the surface?
Corydoras breathe air occasionally, which is normal behavior.
Do Corydoras eat algae?
No, they prefer sinking pellets, bloodworms, and shrimp pellets.
How can I tell male and female Corydoras apart?
Females are larger and rounder than males.
Bronze Corydoras are hardy, fun, and easy to care for. Whether you’re a beginner or an experienced fish keeper, they make a great addition to any community aquarium! Want to give your Corys the perfect home?
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