sk8erboy

I have a strange question that I've wanted to know for years. Does anyone know if fish sleep? I know they can't close their eyes, but when I watch my fish at night, they seem to be sleeping, but they are still aware of me. They have to stay afloat, so they still move their fins. Do they go in some sort of trance, or do they not sleep at all? Strange question, I know, but it is always something I've wanted to know. ttyl

Dino

Actually, half of their brains shut down as they sleep, ( right and left).
Which side is asleep switches out thru the night.

COBettaCouple

my whole brain shuts down when i sleep. :P that's pretty interesting really - learned something new there about how they sleep.

TheEssigs

From what I understand and read, all most all fish spend time in an energy-saving state that can be called "rest" or we can call this behavior "sleep", though it is different than "sleep" as we know it. Many fish rest in, on or under logs at night. Reef fish are active in the day and then 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. Sometimes corydora catfish "rest" on their side, as if dead or lying down, on the bottom of the tank. Many fish "rest" or "sleep" during the day and are active at night instead, but almost all fish sleep and/or "rest". There are exceptions, like marine sharks, that never stop swimming, they HAVE to keep moving to push water through their mouths & gills in order to breathe.