Mix Koi (Assorted Nishikigoi) are large, ornamental freshwater carp bred for their striking, brilliant color combinations and distinct scale patterns, traditionally kept in outdoor ponds.
Popular Varieties: Includes Kohaku (white with red markings), Taisho Sanke (white with red and black), Showa (black with red and white), Yamabuki Ogon (metallic solid gold), and Butterfly Koi (long, flowing fins).
 Size: Very large, growing up to 24–36 inches (60–90 cm) in proper pond conditions.
 Behavior: Highly social, calm, and intelligent pond fish that often learn to recognize their owners and hand-feed.
 Care: Requires outdoor ponds or massive setups (minimum 250–500 gallons per adult fish), heavy filtration, high aeration, and cool-to-temperate water (59–77°F / 15–25°C).