The animal that is not actually a fish is a whale. Whales are marine mammals and are not classified as fish. They are warm-blooded, give birth to live young, and nurse their young with milk.
The animal that is actually NOT a fish is a dolphin. Despite living in water, dolphins are mammals that breathe air and nurse their young with milk. They belong to the family Delphinidae and are highly intelligent creatures known for their playful behavior and communication skills.
