Butterfly Koi FishRelated animal: Koi Fish Interesting facts about Koi fish history and features. Koi can live longer than most other fish. The average lifespan of koi is about 50 years. Another type of Koi fish that I did not know is the butterfly Koi. It is a unique type of koi characterized by its long fins and tail often accompanied by its dazzling color. Many people clam that butterfly koi is the most beautiful type of koi fish. They have also interesting links about the symbolism of Koi fish in some cultures.Submitted by nusia [Write Review]