Do fish sleep and if so should you turn off the light in the aquarium at night?

Fish sleep the same way as dolphins. There are two hemispheres to their brain. One third of the time one half of it is asleep. Another third of the time it’s the other way around. The remaining third of the time both hemispheres are awake and they are at their peak performance level.

@ AstroChuck but how do you know if they are sleeping? Do they like the light off or do they like it on because they are afraid of the dark? :-)

They want the light on so they can see the sharks stalking them.

fish do sleep. they go into this dormant floating state whether the light is on or off. but, yes, i do turn off the light. they do know when the light is turned on because the next activity is possibly feeding.

I leave the aquarium light on a third of the time; otherwise, the snoring keeps me awake.

Better safe than sorry, I say. I leave a night light on for Milo near his litter box, and everyone explains carefullythat cats are not like babies. But my conscience would keep me awake if I did it differently.

Turn your lights off at night. There are a couple of reasons for this. For one, your fish do sleep, some will float in one spot while others will actually just lay on the bottom and sleep.(for instance my mandarin sleeps in the same corner of my tank every night, and turns a light white color while he sleeps, then regains color in the morning.)

The whole idea of having an aquarium is to recreate their natural environment. Its not sunny 24 hours a day in nature. So having the lights on all the time will stress your fish out and most likely lead to a shorter life. Its best to have your lights on a timer so its the same amount of light everyday allowing them to get used to the cycle.

Another great reason to turn your lights off at night is algae. Algae needs light to grow. The more light, the more algae you will grow. By having your lights off part of the time, you will reduce the amount of algae growth so your tank wont get dirty as fast.

If you have any nocturnal fish you could get something like this which will simulate the moon light so you can watch your nocturnal fish, while still allowing your other fish to sleep.

yes fish do sleep, and i think you should not turn of the ligts at the aquarium at night

fish sleep and leaving the lights on all the time isnt good for them it stresses them out

“The whole idea of having an aquarium is to recreate their natural environment. Its not sunny 24 hours a day in nature.” – UberBatman

Correct. A 12ish hour pattern is ideal. I turn my lights on at 7:30am and usually turn them off a little bit later… mostly so I can continue to enjoy my animals for a little longer.

They actually make timers that you plug the lights through that make this a breeze.