There are about 22,000 species of fish in the world, and they are distributed in almost all saltwater or freshwater environments that have not been seriously polluted. These fish living in oceans, lakes, rivers and streams have experienced a long evolutionary period of millions of years and have become accustomed to their different living environments. Different fish have different physiological mechanisms: freshwater fish live in salt-deficient waters, so they need to accumulate salt in their bodies; while saltwater fish are just the opposite. They live in a hypertonic environment, so they must excrete excess salt. Fish that can survive in both freshwater and saltwater are even more amazing. They have both physiological mechanisms of salt accumulation and salt excretion!
In fact, fish are classified according to their salt tolerance. Fish that can only survive in waters with a narrow range of salt are called stenohaline fish; freshwater fish such as goldfish and marine fish such as tuna belong to this type of fish. Fish that can survive in waters with different salinities are called euryhaline fish, such as salmon, eels, and the eye-spotted drum fish found on the Atlantic coast of North America. They can migrate from freshwater areas to slightly brackish waters, and from slightly brackish waters to very salty waters - of course, if the salinity changes greatly, they will need a period of adaptation.
animal tags：
you may also like
The so-called "native cats" refer to cats that have not had much contact with humans in a wild or semi-wild state and have not been domesticated. Generally speaking, the reasons why it is not recommended to keep native cats include the following:1. Health problems: Native cats often do not...
Ragdoll cats are also called Brado cats, ragdoll cats, and doll cats. Their Latin name is Ragdoll. Although Ragdoll cats are the largest in size and weight among all cats, they are indeed gentle and big. They are very friendly to humans and can tolerate children's fighting, so Ragdoll cats are fav...
German Shepherds are a breed of dog with a very high IQ. They are born with good learning abilities and a willingness to obey instructions. Under normal circumstances, German shepherd dogs can communicate with humans through senses such as sound, vision, and smell after birth, and gradually understa...
The pufferfish (also known as the pufferfish) and the pufferfish both belong to the family Pufferidae, and they are usually freshwater or marine creatures, but they differ in many ways. living environment: Agouti (Acanthus): Generally lives in marine environments, but some...
"Dipaizi" usually refers to animals such as "lizards". Lizards are a type of animal in the class Reptiles. They usually have slender bodies and relatively developed limbs. They can run quickly on land, and some species can crawl on trees. They have removable tails that can be used to distract...
Amphibians refer to animals that live in both water and land ecosystems. They often have physiological characteristics adapted to both ecosystems in order to survive in water and on land. Here are some typical amphibians: Tree frogs (such as green tree frogs): Tree frogs...
The incubation period after a cat develops rabies can last from weeks to months, depending on a variety of factors, including the extent of the viral infection, the response of the individual's immune system, and other environmental and health factors. Generally speaking,...
Generally, dog cages are not suitable for raising chickens. Because the structure and size of dog cages are usually designed according to the needs of canines, and the growth and behavioral characteristics of chickens are very different from those of dogs. In addition, dog crate materials are genera...
Email: jsset#163.com (change # to @) Please indicate your purpose of visit! Guangdong ICP No. 2022053326 XML| map| Chinese
