Fish do sleep, and have sleeping problems

Fish sleep regularly just as people do, but their eyes remain open. Why? Because they don't have eyelids! Sleeping habits of fish depend on breed; some seem to be still in open water while others hide under rocks or logs. Fish are very light sleepers, and will wake with the slightest ripple of water.

Some fish even have sleep disorders, like insomnia (such as the Dave Attell Fish, ha ha). Check out these Zzzz-less zebrafish.

This topic was submitted by Laura Johnson