Do Fish Sleep?

[Aveena]

Hey. i have been wondering about this for a while now, as i have my three tanks in my room. I know it may sound like a silly questions but do fish sleep? as when ever i go to bed and look at my tanks my fish just seem to carry on swimming like they would if the light was on.
So if anyone could answer my question please.
All comments appreciated.
Thanks

 

[5teady_2012]

I heard but dont know if its true, that half of thier brain cuts off, and thats why they slighty lean to one side when lights have been out long time.

 

[steelhealr]

Yes...they do. SH

 

[kreacher]

Most all fish spend time in an energy-saving state that can be called "rest", and we might even call their behavior "sleep"

 

[eldomingo]

they're involuntary breathers (they have to remember to breathe like dolphins and sharks etc) so no they don't in the sense that we do, they rest though and go into a kind of trance.

so in a sense they sleep but a large part of their brain has to stay active so they remember to breathe

 

[Aveena]

cool. i've never seen my fish lean to one side for having the light turn off. but i'll look better next time.

 

[Colin_T]

Yep they sleep
Some sleep during the day and come out at night (catfish, eels, etc).
Others sleep at night and are active during the day (tetras, barbs, angelfish, so on).
Some fish sleep out in the water and others sleep among rocks. Cleaner wrasses and parrotfish make a mucous sleeping bag which they spend the night in. It helps stop predators from finding them by smell. In the morning you can often see the little jelly like sleeping bag floating around the tank.

 

[Thomas 2507]

When I look in my tanks at night some of the fish are lying at the bottom and some are swimming around.

 

[Aveena]

ok. well i dont have any parrot fish so i dont get jelly bags. if anything in my tank that stays still its probally my plec during the day. and sometimes the ottos. but otherwise my guppies, flagfish and platies are always swimming about. unless they sleep when i dont see them. because most of the time their near the corner watching me or watching something. or just being pigs and looking for food.
I love my fish either way though. there just so cute to watch.

 

[Bignose]

they're involuntary breathers (they have to remember to breathe like dolphins and sharks etc) so no they don't in the sense that we do, they rest though and go into a kind of trance.

so in a sense they sleep but a large part of their brain has to stay active so they remember to breathe

Well something definitely is amiss here. The parenthetical part about how dolphins have to remember when the breathe describes voluntary breathing. Not involuntary. Whales are the other common example.

That said, I don't think that fish (or sharks, either, per your other example) are voluntary breathers. They may be, but I re-read my ichthyology book's entire chapter on respiration and it didn't mention anything about it being voluntary. Nor can I find anything on the web that describes it as voluntary. All the examples of voluntary breathers are dolphins and whales. Can you cite a reference that describes them a voluntary?

 

[rachh004]

Sometimes in the morning when I turn the tank light on, some of the fish seem startled like I scared them. Normally they see me standing in front of the tank and dont get scared. So it seems like they were sleeping and I woke them