Does the fish sleep?
Yes. They sleep and can sleep at any time of the day or night. Fish sleep with their eyes open because they do not have eyelids (except for some sharks) to close! At the surface level, many fish sometimes seem to be snooze. When snoozing, they respond less, their heart rate slowing and overall movement decreases. Some sleep during the day and only wake up at night, while others sleep at night and stay awake throughout the day. If you watch the fish for a long time, you will notice that they take breaks. They are in trance with their eyes open and seem to float in the place. Why do they move when they are asleep? Sometimes people look at fish when they are asleep and think they are awake because they are still moving. Most fish need to keep moving even during sleep so that they keep a constant flow of water through their gills to maintain the right amount of oxygen in their body. Some large fish, such as sharks, they swim at slow speeds while asleep. Small fish occasionally mo...