The term CARP VARIETY refers to the different types of carp fish, with the most common variety being the KOI, which is a three-letter word. Carp are a type of freshwater fish that are native to Europe and Asia, and they have been kept in ponds and aquariums for centuries. There are many varieties of carp, including the common carp, mirror carp, leather carp, and KOI carp. The KOI carp is the most popular variety, and it is known for its vibrant colors and patterns.