Fish

Fish are aquatic vertebrates with gills, fins, and scales. They are found in nearly all aquatic environments, from freshwater to saltwater, and range in size from tiny species to enormous creatures such as the whale shark.

Anatomy of a Fish

A fish's body is adapted for life in water. Key features include:

Gills: Fish use gills to extract oxygen from water.
Fins: Fins help fish to maneuver, stabilize, and propel themselves through the water.
Scales: Scales provide protection and reduce water resistance as fish swim.
Swim Bladder: This internal gas-filled organ helps fish control their buoyancy.

Diversity of Fish

There are over 33,000 known species of fish, with new species still being discovered. They are incredibly diverse, with adaptations for various lifestyles and environments. Some common types of fish include:

Bony Fish: The largest group of fish, with skeletons made of bone.
Cartilaginous Fish: Includes sharks, rays, and skates, with skeletons made of cartilage.
Jawless Fish: Primitive fish lacking jaws, such as lampreys and hagfish.

Role in the Ecosystem

Fish play crucial roles in aquatic ecosystems. They serve as both predator and prey, helping to maintain a balanced food web. Additionally, many fish species are important for human consumption, supporting fisheries and providing a source of protein for millions of people worldwide.