The Black Telescope Fantail is a variety of goldfish that has a robust body, a long, flowing fantail and protruding, telescopic eyes. The black velvet appearance intensifies with age and sunlight exposure. However, prolonged exposure to excessively high water temperatures can cause the fish to revert to an orange color. As with all types of goldfish, the black telescope fantail prefers a variety of food. It is best to offer a staple of pellets or flake food, but supplement with fresh alternatives such as peas or earthworms.