Catfish is a very common fish, but also a common ingredient, can be eaten. Their appearance is very characteristic, with many unique features, such as their beard, their dorsal fin is very small, and their scales have been reduced and so on. If we touch them, we will find that their body surface is very sticky, just like their body surface has a layer of oil. But it's not really oil on the surface of their bodies, it's just mucus. These mucus play a role in protecting the body of catfish, but also can reduce the resistance of catfish in the water, so that they can move more freely.
As mentioned above, there is a layer of material on the surface of the catfish's body that looks like oil, but in fact this is the mucus secreted by the catfish's surface. Catfish scales have been degraded, belonging to a scaleless fish, at this time they need additional substances to protect their bodies, prevent bacteria from invading their bodies. There are some mucus glands on the skin surface of catfish, and these special structures can secrete a large amount of mucus and form a mucus layer. The slime feels slippery, like oil.
The role of these "oils" is very important. The most important role is to protect the body of catfish, they can replace scales to protect their body, prevent the invasion of some harmful bacteria, but also can block some harmful substances in the water. In addition, mucus can also help catfish maintain their normal osmotic pressure and adapt to changes in salt concentration in water. Moreover is reduces the resistance the function, lets the catfish swim moves saves effort.
