How to Tell If Your Koi Is Pregnant

By Pamela Miller

Japanese koi are not only very beautiful, but they also are sturdy fish that are able to adjust to many climates. Raising Japanese koi requires basic knowledge about their care, but because they are able to adapt to changing weather conditions, they are not as high maintenance as some fish. Koi can grow up to 2 feet in length and this makes raising them a very pleasurable and fascinating experience. Some fish give birth to their young and others lay eggs. Koi are a type of fish that lay eggs.

Look at your koi and try to determine whether the belly looks rounded or a bit bumpy in appearance. A pregnant koi will have a very full, almost "bloated" look about it. It might look like it is holding small marbles inside, but these are simply eggs that it will lay.

Feed your female koi high amounts of protein before it lays eggs if you are aware of the pregnancy. Protein will assist in moving the process of laying eggs forward. A koi must mate in order to lay its eggs. The eggs will attach to a surface such as the surface floor of a tank or pond.

Determine the age of your fish. Koi fish are ready to lay eggs around the age of 3 to 4 years old. An easy way to tell if your koi has reached reproductive age is by measuring its length. If the koi is under 10 inches, it has not fully developed its reproductive organs and, therefore, cannot lay eggs yet.