danios asleep? Question

  1. JoannaB Well Known Member Member

    My older son (6 year old) and I are wondering about whether or not our danios are asleep. They are swimming, but very slowly, at this late hour. (We have a night light on, and the 3 glofish are clearly visible but the regular zebras are not, btw.) Do danios swim while asleep or do they lie down at the bottom of the tank? (In which case I don't think I have ever seen a danio that is asleep.) Other option: I once saw a danio swimming in place like on astationary bike, moving her tail, but without moving forward - was she asleep? When I leaned closer for a better look, she rapidly swam away. How often and how long do danios sleep? And if they swim when asleep, how come they can turn around before bumping into stuff like aquarium wall or decoration? I read somewhere that they do not have eyelids, right? So they sleep with eyes open?
     
  2. Wendy Lubianetsky Well Known Member Member

    Scientists at Stanford University School of Medicine studied Zebra danios, Danio rerio, in aquariums and recorded videos of their nocturnal behaviour using special night-vision cameras.
    After watching hours of footage, researcher Tohei Yokogawa confirmed that the fish droop their tails during the night and sit motionless, either just under the water surface or on the floor of the aquarium and sleep.

    Information researched on: http://www.geochembio.com/biology/organisms/zebrafish/

    Added by Moderator:
    Credit for the above copy and paste goes to PracticalFishKeeping/Published: Matt Clarke Monday 15 October 2007