Goldfish varieties also differ in appearance, color, and patterns. The Carassius auratus, or “sea“ goldfish, is distinguished by its dorsal fin being completely white with two or three black stripes along the upper edge of the dorsal fin. If there are black stripes in a specific area of the Carassius auratus, this can be a hint that this fish belongs to another species, such as the blue-finned salmon. On the other hand, a single white stripe on a gray body indicates a Carassius melanops or night-shade goldfish.