Do aquarium fish sleep?

In aquariums, fish sleep cycles are often determined by interior lights—the fish will sleep when the lights are turned off. Many fish, like minnows and coral reef fish, are active in the daytime and sleep at night while others do the opposite and are active at night instead. read more

Fish sleep but their sleep is more like 'trance' than a sleep as we know it. They rest, have metabolism slowed down but their brains do show the same REM phases as mammals including humans have. Some fish like sharks are thought to have continuously swim during the resting period. and parrot fish secrete a sleeping cocoon that helps hide from predators. read more

Best Answer: Fish do sleep! When they sleep, their eyes remain open, though, because of the whole "no eyelids" thing. When they sleep, they just kind of float in one spot in the tank. read more