All koi are the same species. (besides cross-breeds like butterfly koi and ghost koi) Koi are classified into different pattern types and the rarest of those would be the Ki Bekko. A koi that is lemon yellow and overlained with sumi (the black splotch pattern), Copy and paste this web address and look at the photo of the Ki Bekko. http://www.koisale.com/koi_bekko.htm
Koi fish Koi fish
The Japanese term for koi fish is simply "koi" (ι―). Koi fish are a symbol of good luck, prosperity, and perseverance in Japanese culture.
Koi fish can live in almost any country. Koi are thought to be originally from Japan. Many people have outdoor fish ponds in which Koi are the dominant fish.
a fish, a koi carp
because it is fish
In Japanese, koi fish is written as "ι―" (koi). The character for "koi" represents the colorful carp fish that are traditionally kept in ponds for their vibrant colors.
Nope they sometimes eat there eggs
Koi are a type of specially bred carp.
Koi fish usually have two eyes.
the rarest fish is the super sized golden trout/salmon cross breed
There is no real data to tell us what the rarest marine fish is. Likely the rarest fish has not yet been discovered, because it is so rare.
Koi fish is suitable as a feeder fish for other larger fish. If a human wanted to eat a Koi fish, (which in general unlikely), it would be better eaten dead.