Why are marine fish more colorful than river fish?

It is due to the living environment and the survival war. To avoid enemies stronger than you, the fish must have a color that blends into the environment.

Explaining the cause of marine fish is more colorful than river fish

The river bed is usually blue-gray, so river trout has a pale green color on its back, making it very difficult to be seen by predators.

Its belly is white to match with the sunlight, making the enemy swim underneath. Similar to cold sea fish due to opaque environment ! Colorful sea fishes live in hot waters and they often live near coral reefs, which are brightly colored.

Do fish sleep?

Fish is like many other animals sleep but the other point is that when sleeping does not close their eyes , so many people mistakenly think. The characteristics of the fish when sleeping is to stop swimming and it stands still, but when it comes to sound, it is very sensitive to detect and avoid.

Therefore, it is often observed that when a fish is standing in one place, but it can be picked up and picked up, it will quickly fling and hide. Depending on the type of fish they choose the water level to adapt to sleep, which floats near the surface of the water but there is a kind of nesting on the trunk that grows under water.

Do fish drink water?

Only marine fish are thirsty. Why? All kinds of fish have the same salt concentration in the blood (about 9gr / liter). Fish live in fresh water, so there is more salty blood than the surrounding water. So from this side of the water to the other side (skin cells and blood vessels) because the liquid is not the same salinity. It is an osmosis phenomenon : water from the less salty side penetrates through the membrane to dilute with the saltier side. So the water permeates continuously into freshwater fish body.

To avoid being sucked out of salt, it must push excess water to not change the rate of salt in your blood. So it doesn't need to drink water. And marine fish? Here is the opposite: sea ​​fish blood contains less salt than seawater ! Water tends to run out, primarily through gills! To retain water, marine fish do not 'urinate', or ' urinate ' very little. But even so, it still has a lot of dehydration. The only solution: drink water! But drinking salt water, does it add salt to the body? Fortunately, it has a chemical fertilizer produced by a special cell to remove excess salt!

Herring information together by . anal?

According to a group of three British and Canadian researchers, herring emits sounds from the anus to communicate with each other! This melody takes place at night, but it has nothing to do with farting because of the stomach. The evidence is that the more they gather together, the more bubbles they emit from the anus!