The Endoskeleton of Fish

The endoskeleton of fish is covered with a protective layer called scales. Scales are the outer covering of the fish that serve to protect the underlying skeleton and internal organs. They come in various shapes and sizes, depending on the species of fish.

Types of Scales

There are different types of scales found in fish, such as cycloid, ctenoid, ganoid, and placoid scales. Cycloid and ctenoid scales are the most common types, while ganoid scales are found in primitive fish species. Placoid scales, also known as dermal denticles, are found in cartilaginous fish like sharks and rays.

Function of Scales

Scales serve several important functions for fish. They provide protection against predators, reduce friction in the water, and help regulate the fish's body temperature. Scales also play a role in buoyancy control and can assist in camouflage by reflecting light.

Structure of Scales

Scales are made up of a hard material called keratin, which is similar to the material found in human hair and nails. They are arranged in overlapping rows, allowing for flexibility and movement. The shape and arrangement of scales vary among different species of fish.

Growth of Scales

Fish scales grow throughout the fish's life, with new scales being added as the fish grows. Scales can also be shed and replaced if damaged or worn out. This continuous growth and replacement process help ensure that the fish's protective covering remains intact.

In conclusion, the endoskeleton of fish is covered with scales, which serve to protect the fish and provide various other functions essential for their survival in their aquatic environment.