Ever wondered if and how fish sleep? According to a piece in The Conversation by Michael Heithaus, he was always curious about how fish rest. The marine biologist wondered how in a body of water with predators all around, fish can catch some Zs.

Source: Seeker/YouTube

There are over 35,000 species of fish alive today, making up over 3 trillion fish, and they all somehow manage to find a way in their environments to sleep. Although scientists are still learning how fish sleep, they do know one thing, according to Heithaus, their sleep is not like ours. While people are pretty much out of it and in a deep REM cycle, fish have to stay aware enough to detect an approaching predator, “at least most of the time,” Heithaus said.

However, most fish have sleep cycles just like us. Aquarium fish sleep between seven to 12 hours each day. While most fish are active during daylight and sleep at night, many other fish, like types of eels, rays, and sharks, are nocturnal.

One thing that makes it hard for scientists to study sleeping fish is that most don’t have eyelids. This means that when they are sleeping, you really can’t tell. You can see that fish remain still and stop swimming when they are sleeping as well as their gills pumping less. Fish also often tend to sleep near the bottom or between a spot near rocks and plants to hide away from predators so that the current doesn’t sweep them away.

Some species of fish, like great white sharks, have to swim just to breathe. This means that they are always swimming, even when they are sleeping. They slow their swimming or swim into a current when they are sleeping and seem to be less aware of their surroundings. However, this is not true for all sharks. The draughtsboard shark, for example, can breathe without swimming, and scientists recently observed a shark that sleeps at the bottom.

Source: Discovery/YouTube

Fish are truly magnificent creatures!

According to Counting Animals, “An individual who chooses to take on a vegetarian diet can save over 225 fish and 151 shellfish a year. If just half of the U.S. population (about 150,000,000 individuals) eliminated seafood from their diets, that would mean about 33,750,000,000 fish would remain in the ocean every year.”

Everything nutritious that people believe they are getting from fish can get from other sources. Check out How to Ditch Fish Oil for Plant-Based Sources and Why Flaxseed Oil is Healthier than Fish Oil. Fish often have been exposed to many toxic chemicals like mercury which the consumer then eats when they eat the fish. Fish are also sentient creatures and can feel pain. There is no reason that we need to continue to eat these animals.

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