Calico Ryukin goldfish are a captivating fancy goldfish variety known for their high, curved backs, egg-shaped bodies, and vibrant, mottled coloration. They are a Japanese breed, developed from the fantail goldfish, and are characterized by their pronounced hump behind the head, curved spine, and flowing fins. The "calico" in their name refers to their unique, multi-colored patterns, which typically include shades of red, orange, white, and black.