Koi are the beautiful, ornamental Japanese fish that are very popular and excellent for ponds. They are very attractive and come in vibrant colors. Many people keep these fish in a pond in their garden due to their brilliant ornamental quality, and also because they are comparatively easy to take care of. These brightly-colored fish are a pleasant sight to the eyes.
Breeding these fish is a grueling task. It requires proper planning while taking care of certain factors like temperature, high-quality food, habitat, etc. Apart from these, you need to choose the male and female with care, taking into consideration their age and health. Besides, extensive research and practical experience is necessary to ensure successful breeding.
These fish breed once a year, during the early summer season when there is a change in temperature. The ideal temperature of water for the eggs to be released is 20 ºC. The breeding is also affected by the length of the day. When the days are longer, the eggs mature faster. Plenty of natural foods like algae are formed in the ponds during summer season. This food is crucial for the growth and survival of the fish.
These fish grow up to two feet in length, and so they require a big pond. Ideally, the pond should be at least four to five feet deep, with a minimum of 1,000 gallons of water. The pH level of the water should be 7.4 to 7.5. Ensure that the pH is not less than 7.0, because this is the neutral value. If it is below 7.0, it means that the water is acidic and may destroy the fish.
There should be a continuous oxygen supply in the pond, so you will need good oxygen pumps. Keep these pumps working throughout the night too. Low oxygen levels are not ideal for these fish. The water in the pond should be regularly aerated, and the pond should be free of ammonia, chlorine, chemicals, and parasites. Cover it with nets to keep out predators like cats. Water hyacinths can be planted, as this might help the fish build their spawning spaces. You can also use any other synthetic material that is available in pet stores. Check all these materials for chemicals and parasites before introducing them in the pond.
Prior to breeding, the fish must be fed properly with protein-rich foods and, if possible, isolated. Fish that are too young or too old are not good for breeding. Once the female is loaded with eggs, she bloats up. This is the time when you introduce a male fish into the pond. The ratio of males to females must be 1:1. Do not add more than two males, as this may leave the female battered after spawning, and the breeding process will not be successful.
The spawning process begins once the males and females are together in the pond. The water may become cloudy and odorous. Create a safe nest for the female to lay the eggs in. Introduce artificial nests, or put twigs in the pond for the fish to build a nest. Around a thousand eggs can be released by the female during spawning. This process generally takes place in the early morning.
After the process is over, the males and females should be separated from each other so that they may recover. Special attention needs to be given to the males as they tend to become infected after this process.
A separate pond needs to be created in advance for the hatching of the eggs. This pond should preferably be made from clay. The water in it needs to be aerated regularly, and it should be free of chemicals. Maintain the pH level to 7.5 and introduce an oxygen pump. Also make sure that there are no flies or parasites in the water before transferring the eggs. Allow growth of algae for the fish to feed on.
Once the eggs are released, transfer them to this pond. As Koi fish tend to eat their own eggs, it's necessary to remove these eggs from the tank as soon as they are laid. The eggs are sticky, and hence require careful handling. They hatch within a week. The little fish survive on the food from the eggs for the first day, after which they need to be fed at least four to five times a day for the first few months. While feeding, be extremely careful to avoid overfeeding, as this can kill the fish.
Amongst the many pond fish types, the Koi is the most exquisite one. Breeding it can be very interesting if you have an eye for detail and understand the basic requirements of fish care.