Gold fish do not technically turn white, but lose color pigmentation when not exposed to enough natural sunlight. The cells responsible for maintaining the bright coloring of goldfish respond to light levels. Fish kept i... More »

The most common reasons for goldfish to turn black are genetics and ingestion of colored food. Dark environments also cause goldfish to produce additional melanin, which results in a change in pigment. Disease is uncommo... More »

Ammonia burns are the most common reason that goldfish turn black. High ammonia content in fish tanks causes irritation and trauma to the goldfish's fins. Ammonia burns are white in color and turn black as the goldfish h... More »

www.reference.com Pets & Animals Pets Aquatic Pets

Ammonia burns are the most common reason that goldfish turn black. High ammonia content in fish tanks causes irritation and trauma to the goldfish's fins. Ammonia burns are white in color and turn black as the goldfish h... More »

www.reference.com Pets & Animals Pets Aquatic Pets

A white spot or spots on goldfish is a disease called "Ick," also known as white spot disease. The white spots look like grains of sugar or salt sprinkled on the fish but are actually parasites feeding on the fish. This ... More »

Goldfish babies, or fry, change from black or dark-gray at birth to a golden color by age one. Environmental factors influence the degree of color they achieve. More »

A number of quick, relatively painless methods have been devised to humanely dispatch fish. A commonly used method is clove oil to anesthetize the fish, followed by an alcohol bath to kill the fish. Another option is to ... More »