Special Structures in Fish: Air Sac and Skin

Fish move effortlessly in water. Various co-existing systems in their bodies make this possible. That these systems with distinctive structures and functions relying on one another to function are the signs of Allah’s artistry of Creation.

How Do Fish Move In Every Direction?

Fish use their fins to move back and forth while swimming in water. Yet, this system is not enough to allow them move up and down. Have you heard that fish are also able to move without using their fins?

This system, that is vital for the fish to survive, is a wonder of Creation that works rapidly.

Fish have air sac in their bodies. These sacs can go deeper or up at very short intervals of time. When fish dives deeper, air sacs possess another important role. This is because, the physical effects on fish do change as the fish goes deeper; fish adopts itself to this changing conditions by increasing and decreasing the amount of gas in the air sac.

The balance point of fish is generally created in a way that it passes through the air sacs. This way when it loses its balance fish regains its balance or remains in a desirable position with minor movements of its fins it wants.

Special Skin Preventing Friction

The majority of fish are covered with a very resistant skin. This skin is consisted of two layers called epidermis and derma. Epidermis includes glands releasing mucus. Mucus has a slippery and sticky structure and thus it helps fish decrease friction while moving in water. As a result, it allows fish to move faster. Besides, with its slippery structure it decreases the possibility of being hunted. Mucus has also a significant role in protecting fish against disease causing agents.

Epidermis has also another layer called keratin. Keratin is a strong and stable material formed by the young cells replacing the death of the old cells getting away from the food and oxygen resources in the derma. This layer which is formed by keratin prevents the water to access the fish’s body and thus maintains the balance between the internal pressure and external ambient pressure. In case this layer were non-existent, water would access the body of the fish, which would result in death as the pressure balance were going to be distorted.

As it is clearly seen, there are many systems that facilitative fish’s movements in water. Structures and functions of these systems differ from one another; the absence of only one of them renders the others functionless, which ultimately ends in death in case of any inefficiency or deficit. (For further reading see For Men of Understanding by Harun Yahya)

It is Almighty and the All-Knowing Allah Who creates all these splendid features in fish. The superior Creation of Our Lord is related in the Quran thus:
 

"Glory be to Him! No, everything in the heavens and earth belongs to Him. Everything is obedient to Him, the Originator of the heavens and earth. When He decides on something, He just says to it, ‘Be!’ and it is.” (Surat Al-Baqara, 117)