Raising koi fry require that you follow a specific growth timeline for the koi fry because the fry will grow at a rapid rate. Koi fry begin as small organisms that use the yolk sacs for nutrients. Eventually, they will transform into active swimmers with firm dorsal fins.
Using a growth chart will allow you to monitor the growth of the fry to see if they are meeting the specific benchmarks for size and weight. If the fry are not meeting these benchmarks, then it will become evident that the fry are growing at a slower rate then expected. Feeding the fry is essential for there development.
How to Raise Koi Fry
The food for koi fry will change as they develop. When the fry are consuming the nutrients from their yolk sacs, you must provide microscopic food such as infusoria or green water. You should not provide brine shrimp to fry too soon because this can lead to starvation or bloating for the fry.
After two weeks, you should feed baby brine shrimp approximately six times a day. At this point, the fry will grow big enough to take in food in the form of micro pellets. Provide this food in carefully controlled amount because too much food can create ammonia in the water, and not feeding the fry enough will stall their growth.
The primary factor that determines the growth of koi fry is the temperature of the water. For optimal growth, the water should be in the range of the low to mid twenties Celsius. This is the temperature that allows the koi fry to metabolize efficient.
If the water temperature drops to less than the ideal range, the koi fry will slow in their digestion. If the water temperature goes above the ideal range for the koi fry, the dissolved oxygen in the water will decrease. Using a data grid will allow you to pair water temperatures with specific length and weight benchmarks for the fry.
Based off the data grid, you can adjust the water heaters or shade cloths for the pond. Additionally, as the fry age, you will need to reduce the percentage of the amount of food that you feed the fry. When the water temperature drops below ten degrees Celsius, you must stop feeding the fry entirely.
The color development of the koi fry begins to emerge around the second month of growth. The fry will develop visible patterns on their scales around the third month of growth, which is when they become tosai. Many koi breeders will perform culling of their fry between the first few months of growth.
This allows for the removal of any koi fry that may have deformities or dull colors to their scales. The remaining koi fry should be the top twenty or thirty percent of all the fry that was produced in the breeding facility. The environment and filtration system for the koi fry is essential to its health.
The fry should be kept in small nursery tanks with heavy filtration systems. These fish, they will then be moved to larger tubs or ponds as the koi fry grow. The filtration system should turn over the volume of the tanks hourly.
This helps to convert the ammonia in their water to nitrate through the use of bio-media. An aeration system is also necessary to ensure that the dissolved oxygen in the water remains at or above seven milligrams of oxygen per liter of water. The water should also meet certain standards for health for the koi fry.
The ammonia and nitrite level in the tank should be zero, and the nitrates should be below twenty parts per million. Should the koi fry not meet the standards for water quality, the koi fry may develop health problem that threaten their survival. There are several mistake that should be avoided when raising koi fry.
Moving the fry too quickly to the main pond is one mistake. Ignoring quarantine procedure for viral infections is another mistake. Lastly, feeding the fry during cold snaps is yet another mistake.
Depending upon the health of the koi fry, salt baths or methylene blue can be used to treat any fungal infection. Following the growth curve for the koi fry, they should of been grown into nisai by their second year of life. At this stage, their size will be between thirty and forty-five centimeter.
