Definition: The word "Aphelinus" comes from Greek, and it refers to a type of large fish. It is typically found in the Mediterranean Sea, including the Black Sea and the Caspian Sea. This fish is known for its long, flat fins that are used for swimming, while its strong, muscular body is used for hunting small prey like crustaceans, shrimp, or birds. The word "Aphelinus" was used by ancient Greek philosophers to describe a type of fish known as the "fish of the world."