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.

Sleep means different things to different forms of animal life. The Saunders Comprehensive Veterinary Dictionary sums it up pretty well: A period of rest during which volition and consciousness are in partial or complete abeyance and the bodily functions partially suspended; a behavioral state marked by characteristic immobile posture and diminished but readily reversible sensitivity to external stimuli. Some fish and amphibians reduce their awareness but do not ever become unconscious like the higher vertebrates do. Fish have time periods when they become less aware of their surroundings but their brain waves do not change, and they do not exhibit REM sleep. They aren’t quite asleep but they don’t seem to be fully awake either. Some fish are motionless in the water during the night, while other fish, like rockfish and grouper, don’t appear to sleep at all. They rest against rocks, bracing themselves with their fins. Some freshwater fish, like catfish, swim up under a log or river bank for shelter during the day. Funny: some fish don’t hide the fact that they take an occasional nap. One of the favorite habits of the clown loach, which has alarmed most new clown loach keepers in the past, is that of resting on the bottom of the aquarium on their sides. They appear as though they are dead or sick, but this is just one of the positions that they adopt when resting. 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. But when they sleep the slightest ripple in the water will disturb them. Nevertheless, in some way they rest, just as we do.

Hello; Yes, fish do sleep and stop moving. If you have active fish like Tetras shutting the light off would be good so the other fish in the tank can relax and not be bothered by these nippers. OFM

Sometimes fish take short naps during the day. When it is dark, and all is quiet, the fish will slow down, and will eventually go down to either the bottom or the top of the tank. They will breath slowly, and their fins will either not move, or move a bit. This is very relaxing to watch :).

Im quite unsure of this, mine always seem to be on the move.

They do. All animals need down time Fish have no eyelids and can see when sleeping so that they can awake to danger when they are triggered by stimuli and react accordingly.

Yes, on the river bed.

Fish. They do sleep, even when having sex. This is how we have fish eggs. Resting, is when they lay against a rock or on the sea bed. Doctor Stevie Selby & Rebecca Hales.

Yes they do, but unfortunately they do not have eyelids and must sleep with their eyes open. ='(

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Yes they do FYI "fish fighter".... FISH DO NOT HAVE SEX!!!!! in actual fact the female fish lays their eggs and then the male comes along and sperms on them. THAT is how a baby fish is created! thats all x

Most all fish spend time in an energy-saving state that can be called "rest", and we might even call their behavior "sleep", though it is probably different than "sleep" in most land animals. Many fish, like Bass and perch, rest on or under logs at night. Coral reef fish active in the day, hide and rest in crevices and cracks in the reef to avoid being eaten at night. The resting behavior of fish is very different from their behavior the rest of the day. Many minnows, for example, which are very active in schools during the day, scatter and remain motionless in shallow water at night. Many fish "rest" or "sleep" during the day and are active at night instead, but almost all fish sleep. There are some animals that never stop swimming, like many species of shark, however, they HAVE to keep moving to push water through their mouths in order to breathe, and they may still sleep while moving, we just don't know yet. Write in again soon! Tom F Ihde http://www.newton.dep.anl.gov/askasci/bio99/bio99047.htm

Yes. In water beds.

Fish don't necessarily sleep, but they rest. Since they don't have eyelids they can't sleep, but their minds go blank for awhile at night so research shows.

yes they do u may not see it but they will go to the bottom of the tank and swim VERY slowly and fall asleep you cant notice this because they sont have any eye lids so they cant close their eyes.

yes. its just that you will neer se them sleep because mostly they´ll wake up before you do.

No they cant sleep but they do rest.

Yes

no

My fish do appear to "sleep" when I turn the lights off in their tank-----and though they have no eyelids, they get this "dazed", "hypnotic" look in their eyes when they are resting, and they more or less rest at the bottom of the tank rather than swim around. They appear to be in a "stupor" when they sleep.

They have periods of activity, but don't sleep in the human sense of closing eyes.

Yes.