When your female Koi is old enough (3-5 years), her body will produce eggs. When the water temperature rises to 65-70 degrees, you will start to see signs of spawning. There will be a lot of chasing, the female will be left alone near the bottom and they will eat a lot of food. Mating is said to begin when there is a full moon and the eggs are released early in the morning. The male’s job is to help her extract the eggs and then fertilize them.
In some cases, the female may not release her eggs. Here are some reasons.
The pond is made up of all female Koi.
Koi males in the pond are not old enough to mate.
The Koi is sick and does not carry eggs.
A sure sign that the Koi is sick and does not carry eggs are the scales. If the scales are sticking out or the eyes are popping out, it could be dropsy. This is when the kidneys are failing. You can use a salt bath to help sick fish. Put 1 level cup of salt in a bucket with 5 gallons of water. Put the fish in the bucket for 1-2 minutes and then return it to the pond. This should be done 2 or 3 times a week until the swelling subsides. Another possibility is that a tumor is causing the swelling. This would make the Koi not swim properly.
Listed below are the possibilities of what can happen if the Koi does not spawn (mating) and carry eggs.
1. If the koi does not spawn, the eggs can remain in the koi for several seasons until they spawn.
2. Eggs can be reabsorbed. This means that she will simply make them disappear into her own body.
3. Sometimes the eggs can join the egg. Egg tied is when the eggs rot and this will kill the female Koi.
Not feeding the fish in winter will help the female Koi to reabsorb her eggs if she does not spawn in the spring. You really want it to reabsorb them as this is safe for your fish. You want to prevent your Koi from having the eggs attached to the eggs.
To determine if all of your Koi are female, you can feel their head. A male’s head will feel like sandpaper and a female ready to spawn will be slippery. If you can touch each of your fish, you will know their sex. If you find out that you have a male Koi, they may not be mature enough to mate. On the other hand, maybe your Koi is just picky.
In short, if your Koi is fat and the scales are fine, then you probably have all the females or the males are not old enough to mate. Not feeding the fish in the winter will help the koi to reabsorb their eggs. Get ready to see baby Koi next spring.