Washington State University’s resident feline scientist, Dr. Universe, answers a question from Yun-hee, 12, of South Korea: Do goldfish need eight to 12 hours of light and 12 to 14 hours of darkness to maintain a healthy circadian rhythm?
With help from WSU fish veterinarian Nora Hickey, Dr. Universe explores how daily cycles of light and darkness help regulate the internal clocks that tell animals when to sleep and perform other essential functions.
Readers learn how fish detect light through both their eyes and a transparent area of the skull called the pineal window. They’ll also discover why keeping aquarium lights and feeding times on consistent schedules can help goldfish stay healthy.
The column also examines how changes in daylight help salmon prepare for spawning, triggering major transformations as they return from the ocean to freshwater.
Ask Dr. Universe is a science education project from WSU that answers real questions from curious kids around the world. Readers and listeners can submit their own questions and explore more columns, videos and the Ask Dr. Universe podcast online.
