Saltwater fish can not survive in fresh water. This is because the osmotic pressure of seawater and freshwater is different, and fish gradually adapt to the osmotic pressure of their waters in the long evolutionary process. The osmotic pressure of marine fish is lower than that of sea water, so water will be continuously lost from the body surface, it needs to drink water to supplement, put into fresh water, due to osmotic pressure reversal, water will continue to enter, resulting in its death. Not only that, but many deep-sea fish can't survive in shallow water because they are adapted to the pressure of deep water and will die in places where the pressure is low.
1. Clownfish: Clownfish refers to the fish of the subfamily Anemoninae of the family Pomacentridae. Because there are one or two white stripes on the face of this kind of fish, it is very similar to the clown in Peking Opera, so it gets this name. This fish lives mainly in warm waters and forms a symbiotic relationship with sea anemones. The mucus on its body can prevent it from being caught by sea anemones, and it can also avoid the attack of some big fish with the help of sea anemones, and it can also eat the food left by sea anemone.
2. Archerfish: Archerfish is a fish belonging to the genus Archerfish of the family Archerfishes, and is also a small ornamental fish. This fish prefers animal bait, in the natural environment, when insects are found on branches and leaves near the water surface, it can shoot water from its mouth, thus shooting down insects in the water, so as to prey.
3. Blue Devil: Blue Devil is a tropical ornamental fish of the goldfinch genus of the Pomacentridae family. Its body is 5-6 cm long and blue in color. It is very beautiful. It should be noted that this animal has a strong sense of territory and is very cruel to the fish that dare to invade, so there is a certain risk in mixed breeding.
