Marlin are bony fish (Class Osteichthyes). There are several species including the Black, White and Blue Marlin (shown here). All the species of Marlin are active predators and are very fast swimming. They possess special adaptations that qualify them as fast swimming active predators. They are fusiform shaped, with a highly rigid semilunate (half moon) tail. They also tend to swim with their fins held very close to their body. This makes them highly prized as Game fish. In the specimen here you can see the Marlins bright coloration and its clear counter shading, Counter shading is a form of cryptic coloration. The marlins dark back makes him very difficult to see from above, The Silver belly blends in with the ocean surface when seen from below. Even from the side a fish colored this way will be Harder to see than a fish of a single color all over.