Do fish sleep??

Answer 1

This is a complex question with no simple answer. Deciding if a fish is asleep depends on many factors, one of which is the definition of sleep.

In humans, the transition to sleep (or even closing the eyes) involves specified changes in the pattern of brain waves in the area of the brain called the neocortex. Fishes don't have the same degree of neocortical development as mammals and thus don't display these brain-wave patterns associated with sleep (view figure of a shark brain). So, as far as brain-wave patterns go, fishes don't sleep.

If, however, you define sleep as a combination of a reduced metabolic rate, slowed physical activity, lowered response to stimuli and the assumption of a resting posture, then many fishes do sleep. Perhaps the best-known 'sleepers' are the parrotfishes (family Scaridae). Many parrotfishes find a suitable spot on the seafloor and secrete a mucus envelope in which they spend the night.

Such fishes normally swim away from a diver by day, but can easily be approached and even gently handled at night. Many fishes, however, seem not to sleep. Pelagic (glossary) species such as tunas and some sharks never stop swimming. One theory suggests that during sleep, sensory information (predominantly visual) gathered during the day is processed to form memories. Fishes that swim constantly in blue oceanic waters receive little 'unusual' visual input and require less 'memory-processing time' and thus need no sleep. This is supported by studies on several species of blind fishes that live in caves. These sightless fishes do not sleep.

Having said all that, though, I did enjoy the simple answer of a young neighbour who told me with confidence that fish can't sleep because they don't have eyelids.

Answer 2

LoL , well i soof heared most fishes doesnt go to sleep and some does . i own a fish too but everynight before i go to bed i do check if the fish is really sleeping . my fish isnt sleeped actually i think fishes does lyed buttom of the fish tank and just relax there but i do not turn off the light i just left little light in my room so the fish can see in the dark .

Answer 3

Many species of fish have periods where they are active and periods where they are not. That could be considered sleep; however, fish do not close their eyes because they have no eyelids. As well, some fish (like tuna and shark) rely on water moving constantly through their moths to breathe, so inactivity is not an option for them.

Answer 4

If a fish slept they would fall to the bottom of the lake and water would stop moving throught there gills and they couldn't produce oxygen anymore. So they are always awake 24-7

Answer 5

It sounds like they do! "It’s probable that fish do sleep in some form, whether slowing down or coming to a complete stop, whether hiding or doing it right in the open."

Answer 6

actaully yes people dont think that fish sleep...Fish sleep with there eyes open

Answer 7

Yes, the rest at the bottom of the tank and they are motionless, but they have no eyelids so that don't rest their eyes like we do when we sleep.

Answer 8

yes, all animals have to sleep. When they do, it's just going to look like they are floating still in the water.

Answer 9

They can only sleep with their eyes wide open. Also they can't sleep for very long otherwise they will drift and possibly die.

Answer 10

yes they just don't have eyelids and the always move due to instint or "sleep swimming"