Black-spotted boxfish, Yellow boxfish

   Medium-sized specimens are light brown with blue spots surrounded by black spots or a black border. Larger adults are mustard-brown with blue-green hues and have a protrusion on the upper lip. The fish's body is protected by an exoskeleton, a shell made of fused bony plates. An additional defense mechanism, in addition to the shell, is the ability to secrete toxic mucus when threatened. The blue tail of Ostracion cubicus is the result of a combination of pigments and structural coloration. The cells of the tail contain microscopic structures that reflect light in a unique way. The "blueness" of the tail is influenced by age, lighting, the condition of the fish, and individual characteristics.