Masked Puffer, Arothron diadematus
Image Caption: Masked Puffer image taken in the Red Sea. Credit: Alan Slater/Wikipedia (CC BY-SA 3.0)
The body is olive green or grey having a black mask over the eyes and pectoral fins, with a black border around the mouth.
An interesting characteristic of the masked puffer is that it will find a home in a cave or similar structure and use its own sperm to disguise its scent from predators. When the sperm becomes moldy it will migrate to another area and repeat the process.
The masked puffer lives secluded from other masked puffer fish except during mating, when it will mate in schools; it rests or sleeps during the night.