Do fish sleep like humans ?

Do fish sleep like humans ?

Yes !

Reason: Yes fish sleep. But it’s not sleep as we know it. They don’t have eyelids to close, they sometimes do it during the day, they don’t show the characteristic brainwave patterns like REM sleep seen in humans, and some, including most sharks have to keep swimming in their sleep.
But fishes do have a period of reduced activity and metabolism which seems to perform the same restorative functions as nocturnal sleep does in humans. Some are more obvious about it than others and actually rest on the bottom or in coral crevices, and parrotfish secrete a mucus “sleeping bag” around themselves before they go to sleep. If you get up quietly in the middle of the night you will find your goldfish in an almost trance- like state, hovering near the bottom of the tank making just the minimum correcting motions with its fins to maintain its position in the water column. If you put food in when they’re like this they take noticeably longer than usual to respond, as if they have trouble waking up.

No !

Reason: Most fish do rest. A bit of ‘shut eye’ is difficult for most fish as they don’t have eyelids except for sharks. Most fish  ’switch off’ when safe to save energy and go into daydream mode. You can see this in a fish tank or aquarium – some float motionless in place, some float near the bottom of their tanks, some build nests or nestle  themselves into the seabed or coral for safety and camouflage. …source

Reason 2: Sleep in fish is not extensively studied. Some species that always live in shoals or that swim continuously (because of a need for ram ventilation of the gills, for example) are suspected never to sleep. There is also doubt about certain blind species that live in caves. Other fish seem to sleep, however. For example, zebrafish, tilapia, tench, brown bullhead, and swell shark become motionless and unresponsive at night (or by day, in the case of the swell shark); Spanish hogfish and blue-headed wrasse can even be lifted by hand all the way to the surface without evoking a response. A 1961 observational study of approximately 200 species in European public aquaria reported many cases of apparent sleep. On the other hand, sleep patterns are easily disrupted and may even disappear during periods of migration, spawning, and parental care. … source