Location and functions of different internal organs

a) Spine

• The fish body is built on this main structural framework.
• This unit is connected to the skull at the front and to the tail at the back. Numerous vertebrae that are hollow make up the spine.
• These vertebrae house and protect the subtle spinal cord.

b) Lateral Line

• The lateral line is one of the fish’s sensory organs which helps the fish to detect vibration in the water and to format their direction of source.

c) Swim Bladder or Air Bladder: The swim bladder is a hollow and gas-filled organ. It allows the fish to conserve energy by enabling neutral resilience in water.

• Fishes that are deep in the water need to release air from their swim ladder when they come up this is due to the difference in atmospheric pressure that circulates on the water’s surface.
• Fishes that do not possess an air bladder sink to the bottom of the water if they stop swimming.

d) Gills:

• Gills help the fish to breathe under the water. Gills are weak organs and they should not be touched by the hand when the fish is alive.

e) Pyloric Caeca:

• This organ is present at the junction of the stomach and intestine.
• It has a finger-like projection and its function is to secrete enzymes that help in digestion. It also helps to absorb the digested food.

f) Vent:

• This organ is used to eliminate the waste from the fish body.

g) Gonads:

• Gonads are the reproductive organs of the fish.
• In female fishes, the bright organ that contains a collection of eggs is identifiable during the spawning period.
• The male reproductive organ is much smaller and less white. It produces milt for fertilizing the eggs.

h) Muscles:

• This organ is also used for locomotion.
• This part is usually eaten by man as it contains certain vitamin deposits.