The whitemargin stargazer, also known as pop-eyed fish or tube-nosed stargazer, is one of the strangest creatures of the Indo-Pacific region, especially around Fiji, Tonga and Samoa. The feature that gave them their names is that their eyes are located on the top of their heads, so they are not looking ahead or around them, but towards the sky.
Stargazers prefer warm and shallow waters where the sea floor is covered in sand or mud and is suitable for hiding. They live in waters 5 to 350 meters deep. There is a very good reason why these strange creatures wear their eyes, their mouth and their nostrils on the top of their heads: they spend most of their time buried in the sand of the substrate and they feed on prey that swims above them, so their senses have adapted to their peculiar lifestyle.
It is not only their eyes that allow stargazers to live in hiding. Their relatively large bodies (individuals vary in size, but they stay in the 20-80 cm range) are colored in hues similar to the color of the sand they live in, providing with camouflage so efficient that they are hardly noticeable, even when they are not buried.
Stargazers have several other very special features that further increase their success as predators. They have a special organ behind their eyes, actually a kind of modified optic nerve that charges electrically, sometimes up to 50 volts, and is used by the fish to electrocute their victim before snatching it and they also have a lure similar to sticky tongue for capturing prey more easily. The lure does not look like a lure at all, it sticks out from the mouth of the fish in hiding looking more like a worm and attracts the prey right above the stargazer, allowing this camouflaged predator to snatch its prey and devour it. They also have venomous spine that release a powerful toxin to protect the stargazer against predators.
Stargazers have another special organ on their head called cirrus, an appendage located on the edge of their mouth – it fulfills the role of preventing the animal from swallowing sand or mud while waiting around buried in the substrate. They feed on any prey they can catch, including octopuses, squids and fish. They use their sticky tongue to catch the prey and their numerous teeth to tear it apart.
Very little is known about the reproductive techniques employed by these strange fish. What is known, though, is that male and female individuals look different and they reproduce sexually. They mate seasonally, reproducing mostly during spring and summer. They live in shallow waters, but, when the time comes for the female whitemargin stargazer to lay her eggs, she looks for an area that is shallower than the usual habitat and she lays her eggs there.