Koi fish is one of the most popular freshwater ornamental fish species in the world. This fish comes from Japan and at first, this fish is a fish used for consumption. However, over time, these fish breed and have many variations. Variations that appear have the beauty and uniqueness of each in the scales. Therefore, this fish is used for ornamental fish. To find out what kind of koi fish, here are some types of koi fish along with pictures of koi fish.