Yes, fish can sleep! Fish do not have eyelids to close, so they sleep with their eyes open. Depending on the species, fish can sit on the floor of a bowl, for example, to sleep. Others drift close to the bottom.
Knowing that they don't have eyelids (some sharks do) what they do is they "daydream".
In order to seek protection some species tuckle themselves up in the ocean floors, some just "float underwater" and others go into corals for protection just to mention some.
