Yes, goldfish do sleep, but their way of sleeping is different from that of humans. They show signs of being still with their eyes open or swimming slowly, and they don't have an eyelid structure.
Biological Characteristics of Goldfish Sleep
Sleep State without Eyelids
Like other fish, goldfish don't have eyelids, so they can't close their eyes to sleep. They enter a resting state by slowing down their activities and reducing their metabolism, which is manifested by hovering in the water or staying still with a slight tilt.
Observation Features: The body color of goldfish may fade during sleep, their breathing rate decreases, and they become less responsive to the outside world.
Fragmented Sleep and Alertness
The sleep of goldfish is intermittent. After each period of sleep lasting for a few minutes, they will wake up briefly to confirm the safety of their environment. This mechanism stems from the need for survival in the wild, as they need to be ready to deal with the threat of predators at any time.
Environmental Factors Affecting Goldfish Sleep
Light: Goldfish follow the circadian rhythm and require about 12 hours of darkness per day. Strong light will interfere with their rest.
Water Flow and Temperature: A steady water flow and a water temperature of 20-24°C are most conducive to their sleep. Turbulent water flow or temperature fluctuations will cause stress.
Hidden Spaces: Goldfish prefer to hide among aquatic plants, in the crevices of rocks, or in the sand layer when they sleep to enhance their sense of security.
Comparison of Sleep with Other Fish
Special Sleeping Postures: For example, wrasses will bury themselves in the sand, and parrotfish secrete mucus to form a "sleeping bag".
Migratory Fish: For example, sharks need to keep swimming to maintain respiration and still keep moving while sleeping.
Feeding Suggestions
To ensure the health of goldfish, it is necessary to provide stable water quality parameters, reduce nighttime noise, and arrange hiding places to simulate their natural habitat. If you find that goldfish remain abnormally still for a long time, you need to check for the possibility of diseases.
Conclusion: The sleep of goldfish is a unique behavior that adapts to the aquatic environment. Although they don't have the action of closing their eyes, they meet their resting needs through physiological and behavioral changes.