Watch this Fish in action here: http://www.youtube.com/watch?v=kj-K_p...
Yoji Ookata who obtained his scuba license at the age of 21 and has since spent the last 50 years exploring and documenting his discoveries off the coast of Japan. Recently while on a dive near Amami Oshima at the southern tip of the country, Ookata spotted something he had never encountered before: rippling geometric sand patterns nearly six feet in diameter almost 80 feet below sea level. He soon returned with colleagues and a television crew from the nature program NHK to document the origins what he dubbed the "mystery circle."
Underwater cameras showed that the artist was a small puffer fish who, using only his flapping fin, tirelessly worked day and night to carve the circular ridges. The unlikely artist -- best known in Japan as a delicacy, albeit a potentially poisonous one -- even takes small shells, cracks them, and lines the inner grooves of his sculpture as if decorating his piece. Further observation revealed that this "mysterious circle" was not just there to make the ocean floor look pretty. Attracted by the grooves and ridges, female puffer fish would find their way along the dark seabed to the male puffer fish where they would mate and lay eggs in the center of the circle. In fact, the scientists observed that the more ridges the circle contained, the more likely it was that the female would mate with the male. The little sea shells weren't just in vain either. The observers believe that they serve as vital nutrients to the eggs as they hatch, and to the newborns.

What was fascinating was that the fish's sculpture played another role. Through experiments back at their lab, the scientists showed that the grooves and ridges of the sculpture helped neutralize currents, protecting the eggs from being tossed around and potentially exposing them to predators.