Fish are vertebrate animals that live in water and breathe with their gills, are cold-blooded, most of them have scaly bodies, and usually reproduce with eggs. Some species reproduce by giving birth live. Number of fish species; is more than the sum of the number of mammal, bird, reptile and amphibian species. According to World Atlas, a total of 33,600 fish species live in the oceans today. In just 10 years (1997-2007), 279 new fish species have been discovered in the Mekong River on the Asian continent. Among the fish species in the oceans, there are 70 "flying fish" species and they can take off up to 6 meters with strong winds.
They do not sleep with their eyes closed as we know them, but they are also resting. Fish usually sleep standing still, that is, they are resting. Some ocean fish continue to move even at rest.