The lifespan of koi fish is usually around 70 years, but under ideal conditions, it can exceed 200 years. Based on a comprehensive analysis from multiple sources, the lifespan of koi fish is greatly influenced by factors such as the breeding environment, water quality, and diseases:
1. Normal Lifespan Range
Under home breeding conditions, koi fish can generally live for more than 25 years. If the living environment is good (such as in natural water bodies or professional aquaculture settings), their lifespan can reach 60-70 years.
2. Extreme Longevity Cases
In Japan, there was a recorded case of a red koi named Hanako that lived for 226 years (from 1751 to 1977). However, such cases are extremely rare.
3. Key Factors Affecting Lifespan
- Water Quality and Water Temperature: The optimal water temperature is 20-25°C, and the pH value needs to be stabilized between 7.2-7.5. It is necessary to change the water regularly and control the concentration of harmful substances.
- Breeding Density and Nutrition: Low-density farming can reduce competition for oxygen and the spread of diseases. A balanced diet (containing proteins, vitamins, etc.) can enhance immunity.
- Disease Prevention and Control: Parasitic infections such as white spot disease and anchor worms need to be treated promptly. Otherwise, it will significantly shorten the lifespan of koi fish.
4. The Relationship between Ornamental Value and Actual Lifespan
The ornamental value of koi fish usually gradually declines after 15 years, but their physiological lifespan may still continue for several decades. For example, a koi fish over 70 years old may be culled due to color degradation, but it is not a natural death.
In conclusion, the lifespan potential of koi fish far exceeds that of general ornamental fish. However, the actual survival time highly depends on the breeding conditions. If home aquaculture pays attention to scientific management, it can significantly extend the lifespan of koi fish.