The lifespan of koi fish is significantly influenced by their rearing environment and genetic factors, which can be categorized into the following scenarios:
1. Typical Lifespan Range
In natural environments: Koi fish usually live for 60-70 years, and some individuals can even exceed 100 years.
In home breeding conditions: The average lifespan is about 25 years, but it can be extended to over 40 years with proper care.
Extreme cases: The longest-lived koi fish on record in Japan, named "Hanako", lived for 226 years (from 1751 to 1977), with a body length of 77 cm and a weight of 9 kg.
2. Key Factors Affecting Lifespan
Water space: Koi fish raised in home aquariums are limited in movement, so their body length is usually only 30-40 cm, and their lifespan is relatively short. Individuals growing in ponds or natural environments have a larger size and a longer lifespan.
Water quality management: It is necessary to maintain the water temperature at 20-30°C and slightly alkaline water quality. Replace 1/4 of the water volume every week and equip with a filtration system.
Feeding methods: Scientifically feed omnivorous diets (including algae, artificial feed, etc.) and avoid overfeeding.
3. Age Identification Method
The age of koi fish can be inferred by observing the annual rings on their scales, which have a structure similar to the annual rings of trees, but a microscope is required for assistance.