Instructions
Watch the development of the eggs. Healthy eggs are clear and will go from being soft to hard before hatching. If the eggs do not make this progress, it may be due to a fungal infection.
Check the eggs for damage. Damaged eggs are susceptible to a fungal infection.
Look for the eye of the fish inside the egg. If you do not see an eye, the egg is probably not fertilized or development has stopped. These eggs are likely to become infected with a fungus.
Look for eggs that become cloudy. This is the start of a fungal infection. Remove these eggs as soon as you see them to prevent the spread of the infection.
Watch for the telltale fuzzy white growth on the eggs. This is the most obvious and final sign of a fungal infection.
How to Identify Fungus Cory Eggs
The many species of Cory catfish, such as the elegant corydoras and banded corydoras, and all are unique in their method of fertilizing their eggs. The female will swallow the male's sperm. Then it passes through her gut and is eventually deposited onto the eggs previously laid by the female on her pelvic fins. Once the eggs are fertilized, she then leaves them on a surface in the tank (most any surface will do) to hatch five to six days later. It is during this time that the cory eggs are most susceptible to fungi infection. There are many signs that eggs are likely to get a fungal infection. Once Cory eggs do indeed have a fungus, they will not going to hatch.