Yes, fish do sleep, but it’s quite different from how humans or land animals sleep. Fish don’t have eyelids, so they can’t close their eyes to sleep. Instead, they enter a state of rest where they slow down their movements and metabolism. This resting state allows fish to conserve energy and rest their bodies.
Some fish, like sharks, need to keep swimming even when they’re resting to ensure water passes over their gills, allowing them to breathe. This type of sleep is called “suspended animation” or “quiet rest.” Other fish may find a sheltered spot to rest, where they can stay still while still being able to extract oxygen from the water.
some fish display diurnal rhythms, meaning they are more active during the day and rest at night, while others exhibit nocturnal behaviors, being more active at night and resting during the day. The sleep patterns of fish can vary depending on species, habitat, and environmental factors....See More