The Special Way of Fish to Sleep

Since fish doesn't have eye lash and eye cover, so the fish sleeps without closing eyes. As usually they are hidden, in shell, more over big shell. But some on big stone also biting seaweed in other not to fall down in sleeping.

Shark sleeps while moving. The shark rests in moving. They rest in moving or swimming into deeper bottom of sea, surely, the way it move so slowly.