# how do piranhas sleep?



## illnoize

this might be a dumb question. but how do piranhas sleep? do they just float and stay in one spot?


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## hastatus

Its not a dumb question. Fish don't sleep like we do, since they don't have eyelids. What they do is rest, perhaps shutting off their minds from what is going on around them.


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## Mr. Hannibal

Well, normally they just stay quiet in the bottom while "resting"... but do piranhas sleep? i don't really know, there are many theories as you can see...

_"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."_http://www.answerbag.com/a_view.php/2329

_"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."_
http://www.national-aquarium.co.uk/databas...841&SearchText=

_"Most fish spend part of every day asleep. Being asleep can mean different things to different fish. Some fish (like herring and tuna) are motionless in the water during the night. Other fish, like rockfish and grouper, don't appear to sleep at all. They rest against rocks, bracing themselves with their fins. Also, some freshwater fish (like catfish) swim up under a log or river bank for shelter during the day. By the way, fish can't close their eyes when they sleep; they don't have eyelids."
http://www.discoverymagazine.com/digger/d92dd/d9208ddb.html_http://www.discoverymagazine.com/digger/d92dd/d9208ddb.html

_"Fish don't sleep like we do, since they don't have eyelids. What they do is rest, perhaps shutting off their minds from what is going on around them."_
(Previous post from Frank/hastatus)


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## rchan11

My P does sleep with his head and body pointing down slightly.


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## 2PiRaNhA~2FuRrY

rchan11 said:


> My P does sleep with his head and body pointing down slightly.


how do you know for sure that your piranha are sleeping??


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## ronnie

my P's just lay there motionless and their head is almost pointing down


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## Dawgz

mine just sits all the way in the corner of the tank behind the driftwood away from the powerhead current and just leans against the glass or the drifwoot and just sits there, if i come up to the tank, slowly itll wake up i guess and then be surprised, and in doing this will come to attack me....i tried to get it on camera but the lighting is soo poor









My puffer sleeps in the crack of the big rock i gave him, he just slides inside, turns around and pokes his head out and then just rests, the way i know he wakes up is his side fins start to move very fast from a no movement state....and at this point he comes up begging for food..like he always does any givin time of the day.


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## Coldfire

Mine stabilize their "swim-bladders" to a natural buoyancy and float about one inch off the bottom.


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