Cory catfish, or Corydoras as you might know them, are simple fish that are easy to care for and breed.
However, even with simple fish, it’s important to know and understand the species so that you can be prepared for the process, and know how to properly care for them as well.
Take a look at this simple guide to help you learn more about Cory catfish eggs, what to expect from the breeding process, and everything you should know about the eggs too.
What Do Cory Catfish Eggs Look Like?
If you have multiple fish intermingled together, it can sometimes be hard to determine whose eggs are whose. If you are breeding fish, it’s much better to separate the species so you can keep them apart.
However, sometimes Corydoras eggs are challenging to spot. There isn’t anything overly spectacular about how they look, and they can easily blend in with rocks or other elements in the tank.
Another thing to know is that eggs might be spread out, although you will generally find anywhere from 10-20 in a single grouping of eggs. These numbers are what will make it easier to find them, but they could be just about anywhere.
The eggs get spread out like this as a protection mechanism. The instinct is to make sure that a predator can’t get all of the eggs so the females spread them out.
These eggs will be very small, and just be a simple white color. They are round, but measure less than 2 mm per egg. This is only about 1/16 of an inch, and comparable to something like the very tip of a crayon when it is brand new. One egg alone might be almost impossible to spot.
Over the first few days, the eggs do start to turn orange, and maybe even have black spots on them. This is how you can tell for sure that a Cory Catfish egg is fertilized.
How Many Eggs Will Cory Catfish Lay Each Time?
As you plan your breeding processes, knowing how many eggs or little fish to expect is helpful. This can help you plan for any tank or pond movements, as well as how often to breed, or how much space you need.
Each time a female lays eggs, it can range from 10-50 eggs in a single spawn. Remember that these will be placed in batches of 10-20, so there may be several batches of eggs throughout the tank.
How the total number of eggs is laid really depends on the species of Corydoras in the tank. Some will lay all of their eggs at one time, while others might lay them over a period of several days.
You can condition your adult Cory catfish to better control their laying. You can also control the laying environment, which might be helpful in some cases as well.
How Often Will Cory Catfish Lay Eggs?
If you are working on breeding Cory catfish regularly, this can be a challenge. When they will lay eggs is unpredictable in many ways. There is no routine schedule or expectation for their egg spawns.
If you are following proper care, and you have set up ideal breeding environments for the Cory catfish, they could potentially spawn every 1-4 weeks. However, when they lay eggs, they might require some recovery time before spawning again. This is particularly true of highly-conditioned Corydoras.
Simulating a natural environment is much better for the laying process, as conditioning your Corydoras might negatively affect the egg laying process and timeline.
These fish generally lay their first batch of eggs somewhere between 6-9 months old, provided they are in appropriate conditions and have mates available to them.
How Long Do Cory Catfish Eggs Take to Hatch?
Cory catfish eggs do not take long to hatch at all. It can take up to seven days from the time they are laid, but hatching could occur in as little as three days.
What affects this timeline the most is the temperature of the environment for the eggs. Ideally, the Cory catfish environment should be somewhere between 72 and 78 degrees Fahrenheit.
Warmer temperatures are more inviting, and will allow the eggs to hatch faster than if the water is too cool. This is pretty common among fish eggs, and not just for Corydoras. That being said, you need to be mindful of managing temperatures, because Cory catfish actually matter better at slightly cooler temperatures.
You will likely cycle the water, depending on your stage of the breeding, laying, and hatching process. You might also benefit from keeping separate tanks for breeding, that are kept about 3 degrees cooler from the main tanks.
Will All Corydoras Eggs Be Fertilized and Hatch?
Just because a Corydoras lays 50 eggs does not mean every egg will hatch. It’s simply impossible for a male to fertilize every egg. If you bred your Corydoras, watch closely for eggs so that you can remove any unfertilized eggs and prevent harm from coming to the fertilized eggs.
We will discuss more on care in a moment.
In most cases, there will be more fertilized eggs than unfertilized eggs, but there is no guarantee to a number or percentage of what you will get. Unfertilized will not hatch, while fertilized eggs should hatch unless a problem occurs.
How to Take Care of Cory Catfish Eggs
If the intent is to breed your Cory catfish successfully, you will need to be prepared to take care of the eggs. In all actuality, this is much easier if you have multiple tanks to work with. You can use the same tank for breeding as you do to hatch the eggs, as long as you adjust the temperature appropriately in between.
That tank could have the temperature reduced slightly for breeding. Once breeding has happened, you remove the parents back to their respective tanks, and increase the temperature to an ideal egg temperature.
When you find the eggs, move them to the main tank, which shouldn’t have any Cory catfish in it at the time.
Now, here are some steps for caring for those eggs.
1. Separate the Eggs from The Females
If you’ve heard rumors that female Corydoras will eat their eggs, it is true. It’s up to you to be observant following the breeding process so that you can prevent this from happening.
Monitor closely for eggs in the female tank, and be sure to check several surfaces since they could be spread out. They will lay on any hard enough surface, which could include rocks, substrate, plants, leaves, and more within the tank.
When you see eggs, remove them quickly. Be very gentle, and use something gentle to handle these eggs. They are fragile and easy to damage.
2. Remove Unfertilized Eggs
Unfertilized eggs can develop bacteria on them, which is why you want to remove them. That bacteria can spread to the fertilized eggs, and ruin the entire batch if not taken care of.
It may take a day or two for fertilized eggs to start changing colors, but when they do, they will turn a brownish color, or have speckles of black on them. Any egg that is not fertilized will remain white, and the layer of bacteria that develops will also be white.
If some eggs start turning, and others do not, this is a good time to begin that separation process. Just sort through them gently, and dispose of any eggs that are not fertilized to prevent the spread of bacteria.
3. Manage the Egg Environment
When you move the eggs to a separate tank, be sure that the water is warm enough. Remember that this is best at 72-78 degrees. A warmer temperature may encourage the eggs to hatch faster, and also improve the rate of survival among the eggs.
Some other things that may be helpful in the environment are as follows.
- Aeration from an air pump will provide necessary oxygen to the eggs, moving water and keeping the eggs safe from things like mold and bacteria that happen with non-moving water.
- If you spread the eggs out within the tank, this protects the other eggs in case one was to go bad. Remember to be gentle and take this process slow as separating Corydoras eggs can be a challenge.
- Treat the tank with an antibacterial solution that is gentle and acceptable. This helps to reduce and eliminate bacteria within the environment.
- Track and manage the water as necessary, changing it frequently if needed. You need to keep dirt at a minimum, and ensure the oxygen levels are stimulated within the tank.
Check this video to know more:
Hatching Cory Catfish Eggs and Caring for Babies
Within 3-7 days, those well cared for eggs are going to hatch and bring forth a host of baby Cory catfish. Give those babies some time to grow before you put them back with the adults, as sometimes the adults will also eat the catfish fry.
With the fry being in their own tank, they have fewer stressors, are able to eat better, and can grow healthy and fast. Let them grow out here, and then add them to your adult tanks when they are big enough.
As they are growing, be sure to use high-quality food, keep the tanks clean, and stimulate oxygen for the growing fry.
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Final Thoughts
While this may seem like a lot of information, growing, breeding, and hatching Cory catfish is not overly difficult. You simply need to be able to provide separation at certain stages, and maintain the tanks in an ideal state.
Once you get your tanks set up, and get a process down, you will be able to breed and enjoy Corydoras for as long as you like.