WONDER #1213: Do Fish Sleep with Their Eyes Open?

Question 1 of 3

Why do fish have to sleep with their eyes open?

  1. to protect from predators
  2. to keep an eye out for food
  3. lack of eyelids
  4. to watch their children

Question 2 of 3

Most fish keep moving while sleeping to keep water flowing over their gills to make sure their bodies have enough of what?

  1. water
  2. oxygen
  3. nitrogen
  4. food

Question 3 of 3

Which fish secretes a jelly-like “sleeping bag” made of mucus before it rests?

  1. parrot fish
  2. goldfish
  3. shark
  4. whale

Check your answers online at https://www.wonderopolis.org/wonder/do-fish-sleep-with-their-eyes-open.