Do Fish Cry? Do fish Sleep?

Fish yawn, cough, and even burp. But they don’t get choked up.

Crying? says Monterey Bay Aquarium’s retired senior marine biologist Steve Webster, is an emotional response made only by big-brained mammals.

Crybabies are "self-aware and can reflect upon past events, make projections about future events and engage in lots of other complex cognitive behaviors," Webster said.

"Since fishes lack the parts of the brain that set us apart from the fishes—the cerebral cortex—I doubt very much that fishes engage in anything like crying," Webster told LiveScience. "And certainly they produce no tears, since their eyes are constantly bathed in a watery medium."

Do fish sleep?

Most all fish spend time in an energy-saving state that can be called "rest", and we might even
call their behavior "sleep", though it is probably different than "sleep" in most land animals.
Many fish, like Bass and perch, rest on or under logs at night.

Coral reef fish active in the day, hide and rest in crevices and cracks in the reef to avoid being
eaten at night. The resting behavior of fish is very different from their behavior the rest of the day.
Many minnows, for example, which are very active in schools during the day, scatter and
remain motionless in shallow water at night. Many fish "rest" or "sleep" during the day
and are active at night instead, but almost all fish sleep.

There are some animals that never stop swimming, like many species of shark,
however, they HAVE to keep moving to push water through their mouths in order to breathe,
and they may still sleep while moving.