Corydoras catfish—affectionately known as cories by aquarium enthusiasts—are some of the most popular freshwater bottom-dwellers. Their docile natures and social personalities make them a perfect fit for a wide range of setups. They also tend to breed readily in home aquariums with only minor interventions.
In this guide, you’ll learn everything you need to know about breeding corydoras. We’ll start with a quick overview of Corydoras breeding basics, including how often do Corydoras lay eggs.
Corydoras Breeding Basics
There are over 170 described species of corydoras catfish, with an estimated 100 more that have yet to be given scientific names.
Popular species include Sterbai cories (Corydoras sterbai), Panda cories (Corydoras panda), Peppered cories (Corydoras paleatus), and Bronze cories (Corydoras aeneus). Though corydoras come in a wide variety of colors and patterns, their breeding habits are pretty similar across the board.
Corydoras catfish are egg-layers. More specifically, they produce small, sticky eggs and deposit them on surfaces in the tank.
Popular spawning sites include the glass walls of the tank, wide-leaved plants, and other decorations. During spawning, the female cory deposits the eggs then the male follows behind to fertilize them.
Setting Up the Tank
If you want your Corydoras to live long and healthy lives, it’s always a good idea to research the individual species you’re cultivating before setting up your tank. As South American catfish, cories prefer warm water with a slightly acidic to neutral pH and lots of vegetation in their tank.
The ideal temperature range is 72-82°F and the pH should be kept between 6.5 and 7.8. Perhaps more important than water parameters, however, is keeping corydoras in sufficiently large groups.
In the wild, corydoras have been known to live in large groups numbering in the hundreds. In the home aquarium, however, it’s best to keep them in groups with no fewer than six of the same species.
Dwarf corydoras can be kept in small groups in nano tanks at least 10 gallons in volume, but most species do best in tanks 20 gallons or larger.
Planted tanks are ideal for corydoras catfish, and it’s best to stick with fine, smooth substrate like sand or very fine gravel. Cories have sensitive barbels on their noses, which can be damaged by sharp substrate.
Decorate your tank with a variety of aquarium plants, such as carpeting, rooted, and floating plants. Feel free to include other natural elements like driftwood and rocks as well.
Conditioning Your Fish
As with any aquarium fish, breeding corydoras successfully requires your fish to be in good condition. Generally, this means they’ve reached the age of sexual maturity and they’re well-fed and healthy.
To condition your cories, maintain a nutritious staple diet of sinking pellets or wafers, but start to supplement it with richer live, frozen, and freeze-dried foods.
You may also want to start taking a closer look at your corydoras to determine the gender makeup of your group. Male corydoras tend to be slimmer in profile and smaller in overall size than females.
If you want to control the timing of a spawn, you can condition the males and females in separate tanks. It’s best to keep the females in the breeding tank and remove the males when you’re ready to trigger a spawn.
Triggering a Spawn
In the wild, corydoras typically spawn during the rainy season when falling rain cools the water in their habitat by several degrees.
You can replicate this effect by siphoning out at least 20% of the tank volume and replacing it with water 5-8°F cooler. Some hobbyists also recommend adding airstones to the tank to boost oxygen levels.
With the introduction of cooler water, many cories will initiate spawning behavior immediately. It usually starts with a flurry of activity, often with males chasing the females around the tank.
Eventually, the males and females will pair up and start to look for spawning sites, then begin depositing eggs. During a spawning period, a pair of corydoras will typically deposit eggs in several places around the tank, up to 200 or 300 in total.
Though wild cories tend to breed most prolifically during the rainy season, they’re sporadic breeders and can spawn at any time if the conditions are right.
If you have a large group of corydoras in your tank and perform regular water changes, you might notice near-constant spawning activity, especially if they have enough space to swim, explore, and establish their own territories.
Caring for Corydoras Eggs and Fry
If you plan to breed corydoras, you’ll need to decide whether you want to raise the fry in a separate rearing tank or attempt to keep them alive in the breeding tank. While Corydoras eggs are adhesive enough to stick to tank surfaces, they’re generally easy to remove.
You can move the eggs to a separate tank or even move them to a more appropriate location in your breeding tank—somewhere they’ll be kept safe from predation.
It takes about 48-72 hours for corydoras eggs to hatch, and the fry will absorb the remains of their yolk sac for another day or two. Eventually, they’ll move toward the bottom of the tank and start foraging for food.
Corydoras fry are small enough to feed on microfauna in the tank, but if you want them to survive, you’ll need to supplement their diet with small foods like finely crushed flakes, micro worms, or powdered fry food.
Feed your corydoras fry small amounts of food several times a day and perform regular water changes to keep the tank clean.
Depending on how many fry there are, you may need to separate them into multiple tanks as they grow bigger. Eventually, they’ll be large enough to accept the sinking foods you feed the adults.
Wrapping up
So, how often do corydoras lay eggs? The answer depends on a variety of factors - from water conditions to group size - but with the right setup and care, these catfish can spawn frequently, sometimes even on a near-weekly basis.
Breeding corydoras at home can be a rewarding experience, especially when you see your efforts result in thriving fry and a happy, active tank.
At Shrimpy Business, we pride ourselves on offering top-notch aquarium supplies, live plants, and high-quality foods, trusted by freshwater hobbyists across the community.
Contact us today to learn more about creating the perfect environment for your corydoras and supporting them through every breeding stage.