Do fish sleep?
Yes and no. Most fish make not have got eyelids, so technically they cannot stopping point their eyes to sleep. They make however remainder in different ways: many eat and swim during the twenty-four hours and stay inactive at night, while some are always semi-resting (daydreaming) as they virtually pass their whole lives motionless.
Do fish wee?
Yes! Similar to humans, fish have got an internal organ called kidney to assist filter the nitrogenous waste material in the blood, to be passed out as urine. Some of the piss is also diffused through the gills.
Fish's kidney have an other function: to regular the amount of H2O in its body. In nature, H2O be givens to flux from a less salty environment to a more than salty 1 in a procedure called Osmosis. Since a fish's organic structure is less salty than salt water, its organic structure be givens to lose H2O to the milieu through Osmosis. The fish's kidney have to work difficult to go back as much H2O to the organic structure as possible. On the other hand, freshwater fish's organic structure is more than salty than the milieu and it be givens to absorb too much water. Its kidney have got got to pump out as much H2O as possible.
Isn't it interesting that seawater fish wee little, while freshwater fish wee a lot?
Fish don't have ears, right?
Fish actually have ears (ear-holes) inch their heads, but they make not work very well. Instead, they "hear" from a line of sensitive receptors located on both sides of the body. Fish are able to observe H2O current and quiver in the surroundings, including the movement of fish and other animals nearby.
By the way, most fish have got very good sense organ and their eye-sight is as good as humans.
How can a fish stay in H2O (instead of floating like us)?
Unlike human beings, fish's organic structure tissue is actually denser than water, so fish don't (and can't) float like us. However, their organic structures have got to make something to avoid the antonym -- sinking into the deep waters! This is achieved by an alone organ called swim bladder, which incorporates gas and modulate its degree such as that the denseness of the overall fish is similar to the denseness of water. Therefore, if the swim vesica makes not work properly, the fish cannot swim, may lose its balance and even turn upside down.
Can fish swim backwards?
Most can't, because their flipper are not designed to "paddle" backwards. Exception includes fishes in the eel family.
Why and how make sea squab blow up themselves?
When in water, sea squab (also called blowfish fish and balloon fish) can quickly blow up by pumping H2O into particular sacs. When taken out of water, the pouches are filled with air instead, which make the fish looking like a balloon.
The sea squab don't make this for fun; it is entirely for defense. The attacker, seeing a suddenly "blown up" fish, usually hesitates for a few seconds, giving the sea squab a opportunity to acquire away. Some sea squab can bring forth powerful poisonous substance (neurotoxin) in their internal variety meat and skin, making it unpleasant or even deadly for their attackers. These particular types of sea squab have got bright colours as a warning to the predators.
Did you know…
The meat of sea squab is considered a highly-regarded delicacy in Japan, because of the taste sensation and the fact that the fish is toxicant (it's food only for the brave!). If the meat is not prepared properly (for example, poisonous substance from the internal variety meat is spilled over), the poisonous substance may do numbness in lips and tongues, vomiting, comatoseness or even decease from musculus paralysis.
However, smart people have got set the poisonous substance in good use: a drug (Tectin) developed from this poisonous substance is used as a powerful hurting stand-in for quite a few malignant neoplastic disease patients.
So adjacent time, in improver to showing off your catch, retrieve to boast out your cognition on fish as well!