I have a koi pond at home.  Koi are considered colored varieties of Amur carp.
Oh interesting, Ive been actually wanting to get some for my small pond, Are they hard to take care of? 
Not really.  They are coldwater fish and they have a great ability to adapt to many different climates. 
Oh very nice, I suppose they would be a good fish choice then, How big do they generally get? 
Koi are pretty small, similar to goldfish.  They stand out due to their patterning and coloration.
Oh got ya, I have seen them before at our local park, there is a giant pond there, How long do they love for?
Carassius gibelio") led to the development of the goldfish.
The Amur carp ("Cyprinus rubrofuscus"), a member of the cyprinid family species complex native to East Asia, was aquacultured as a food fish at least as long ago as the fifth century BC in China, and Jin Dynasty (fourth century AD) texts mentioned carp with various colors. The Amur carp was previously recognized as a subspecies of the common carp (as "C. c. haematopterus"), but recent authorities treat it as a separate
group of fish originally found in Central Europe and Asia. Various carp species were originally domesticated in East Asia, where they were used as food fish. Carp are coldwater fish, and their ability to survive and adapt to many climates and water conditions allowed the domesticated species to be propagated to many new locations, including Japan. Natural color mutations of these carp would have occurred across all populations. Carp were first bred for color mutations in China more than a thousand years ago, where selective breeding of the Prussian carp ("