Carp come in three Varieties depending on the scale formation. Common and Mirror carp are the most common and you will occasionally see Leather Carp although they are now quite rare. Carp will grow very large quickly so please bear this in mind before buying.
They will very quickly outgrow an aquarium and should really be housed in a large pond/lake or a garden pond with filtration. They are very messy and will try to uproot all of your plants!