Why are goldfish gold?

The goldfish's signature gold color is the result of a mutation that affects the way it produces pigment cells called chromatophores. In their natural state, goldfish are actually olive green in color. The gold color is a result of a genetic mutation that causes the fish to produce more of a certain type of pigment cell called a xanthophore. Xanthophores contain a yellow pigment called carotenoid, which is also found in carrots and other orange-colored vegetables. The amount of carotenoid produced by the fish determines the intensity of the gold color.

In addition to the gold color, goldfish can also come in a variety of other colors, including red, orange, black, and white. These colors are also the result of different mutations that affect the production of pigment cells.