What are the three classes of fish and give an example each?

1. Mammalia: These are warm-blooded vertebrates with fur or hair, mammary glands, and give birth to live young. Example: Dolphin (although they live in the water, they are mammals)

2. Aves: These are warm-blooded vertebrates with feathers, wings, and lay eggs. Example: Tuna

3. Reptilia: These are cold-blooded vertebrates with scales, lay eggs, and breathe air with lungs. Example: Sea Turtle

Within the class Pisces (fish), we can further categorize them into three subclasses:

1. Agnatha: These are jawless fish, the most primitive group. Example: Lamprey

2. Chondrichthyes: These are cartilaginous fish with skeletons made of cartilage. Example: Shark

3. Osteichthyes: These are bony fish with skeletons made of bone. Example: Goldfish