Fish in the sleep time is the need to turn off the lights. Many fish need to find a shady environment when they rest, and turning off the lights can also make them more comfortable when they sleep. In addition, turning on the light for too long can easily lead to algae explosion in the fish tank, which is not conducive to the survival of fish. There are also some nocturnal fish that need to turn off the lights before they can move.
1. Hide and sleep: For many fish, in order to prevent being attacked by other fish while resting, they tend to hide. For example, mullet, snapper and so on, they will hide behind the rocks when they sleep, while carp and crucian carp will get into the water and grass.
2. Hide in the sand: For some benthic fish, it is not realistic for them to hide in rocks or aquatic plants, but they can hide in the sand at the bottom of the water, which can also avoid the attack of natural enemies, in order to avoid being eaten while sleeping.
3. Bubble wrap: Some fish can secrete a gelatinous substance when they sleep, such as split mouth fish and parrotfish in the South China Sea. This gelatinous substance will become hard when they meet the water, and the fish can drill into it, while leaving a mouth for breathing.
4. Sleeping while swimming: There are also some fish with a strong metabolism, which need to swim from birth to death, and sleep is no exception, so that they can breathe normally, such as tuna, sharks, etc., so they will sleep while swimming.
