The reason why fish keep their eyes open when sleeping is because fish do not have eyelids, so fish eyes cannot be closed. This is why many people mistakenly believe that fish do not sleep.

Situation 1: Sleeping in the dark

If you carefully observe the goldfish you raise, you will find that at night, they will hide in dark places such as small rockeries and water plants in the fish tank and remain motionless. This is what happens when a goldfish sleeps.

Situation 2: Drilling into the sand

Some fish, such as the sea pig fish, the wrasse, and the golden fish, live at the bottom of the ocean. When night comes, they will get into the sand and sleep motionless. This is both safe and effective in prevention. Damage from natural enemies.

Situation 3: Penetrating Bubble

Some fish, such as the slitfish and the South Sea parrotfish, have a special gelatinous substance permeated in their bodies. When they want to sleep, they will blow big bubbles like children, and the gelatinous bubbles will touch the water. Tough, and then they get into the bubble, leaving only a small hole near the mouth, just like in a sleeping bag.

Most fish that live in fresh water sleep behind rocks and in the darkness of aquatic plants. Carp and crucian carp burrow into the water plants, while mullet and bream sleep on the back of the rocks.

Situation 4: Swimming while sleeping

Fish with a migratory habit sleep while swimming. Swimming all the time because they must continuously spit out water to maintain breathing, such as sharks, tuna, mackerel and carp, swim back and forth continuously during the day and night, making it difficult to know when they are Sleep; when to wake up.

Fish can sleep, and their eyes are open when they sleep.

                    </p>

                </p>