I just bought some Koi fish for my pond. These are Amur carp fish with different colored variants.
They are amazing fish i have heard the live up to 30 years or something like that 
The koi are popular in Japan where they recognize many varieties.
Do you know how old was the longest living koi fish?
I do not. But the different Koi fish are distinguished by their scalation, patterning, and coloration.