This little animal is less than a quarter of an inch long. During the day, Cypridina live on the ocean floor. During the night, they swim around looking for food. Cypridina leave behind a little patch of blueish light as they swim through the ocean. This trait of a living creature giving off light is called bioluminescence.
Insects range in size from gnats like tiny dots to beetles as big as rats.
Insects are covered by a hard casing called an exoskeleton. Their muscles are attatched to this exoskeleton like our muscles are to our bones. The reason insects only get as large as they do is because their muscles would not be able to support an exoskeleton any larger. Fish do sleep. While sleeping, a fish may continue to open and close its mouth and gently sway its body from side to side.