I get this question a lot. They don’t have eyelids… how do they sleep?
If you’ve seen people sleeping with their eyes open, then you’re halfway there.
This is how (pictured below):
They stay still, moving their fins intermittently, to maintain their position in the water.
Dr Richmond Loh
DipProjMgt, BSc, BVMS, MPhil (Pathology) Murdoch, MANZCVS (Aquatics& Pathobiology), CertAqV, CMAVA, NATA Signatory.
THE FISH VET, Perth, Western Australia.
Veterinary Medicine for fish.
P: +61 (0)421 822 383
2014 President WAVMA.org